sistem mikropemproses & pengawalmikro

Thava kumar A/L Devanayagam 1

SISTEM MIKROPEMPROSES

& PENGAWALMIKRO

(E 4160)


Pengenalan kepada mikropemprosesIntroduction to Microprocessors

Chapter 1


What is a Microprocessor ?• A microprocessor is a multipurpose, clock-

driven, register-based electronic device that• reads binary instructions from a storage device

called memory, accept binary data as input and processes data according to the instructions given and provides results as output.

• Ex: 8085, 8086, Z80, 6800, Pentium processors etc


Microprocessors

• The microprocessor is a programmable integrated device that has computing and decision-making capability similar to that of the central processing unit (CPU) of a computer.

• The fact that the microprocessor is programmable means it can be instructed to perform given tasks within its capability.

• The microprocessor is a clock-driven semiconductor device consisting of electronic logic circuits manufactured by using either a large-scale integration (LSI) or very-large-scale integration (VLSI) technique.


Microprocessors

• A typical MPU has three basic parts inside. They are:– the Program Counter (PC)– Memory, and – Input / Output (I/O).

• The Program Counter keeps track of which command is to be executed.

• The Memory contains the commands to be executed. • The Input / Output handles the transfer of data to and

from the outside world (outside the MPU physical package).

• There are many other actual parts inside the MPU, however, we will learn about every single one, one step at a time.


Microprocessors

• Nowadays, the microprocessor is being used in a wide range of products called microprocessor-based products or systems.

• The microprocessor can he embedded in a larger system, can be a stand alone unit controlling processes, or it can function as the CPU of a computer called a microcomputer.


Microprocessors

• The microprocessor communicates and operates in the binary numbers 0 and 1, called bits.

• Each microprocessor has a fixed set of instructions in the form of binary patterns called a machine language.

• It is difficult for humans to communicate in the language of 0s and 1s.

• Therefore, the binary instructions are given abbreviated names, called mnenomics, which form the assembly language for a given microprocessor.


Microprocessors

• A typical programmable machine can be represented with four components: microprocessor, memory, input, and output.

• These four components work together or interact with each other to perform a given task; thus, they comprise a system.

• The physical components of this system are called hardware.

• A set of instructions written for the microprocessor to perform a task is called a program, and a group of programs is called software.


Microprocessors

• The microprocessor applications are classified primarily in two categories: – reprogrammable systems and – embedded systems.


Microprocessors

• In reprogrammable systems, such as microcomputers, the microprocessor is used for computing and data processing. These systems include:– general-purpose microprocessors capable of

handling large data, mass storage devices (such as disks and CD-ROMs), and peripherals such as printers;

– a personal computer (PC) is a typical illustration.


Microprocessors

• In embedded systems, the microprocessor is a part of a final product and is not available for reprogramming to the end user. Example: – copying machine – washing machine.– Air-conditioner– Etc.


Microprocessor, CPU & Microcontroller

• Microprocessor (MPU) - a semiconductor device (integrated circuit) manufactured by using the LSI technique.– It includes the ALU, register arrays, and control circuits on a

single chip.

• CPU - the central processing unit. – The group of circuits that processes data and provides control

signals and timing. It includes the arithmetic/logic unit, registers, instruction decoder, and the control unit.

• Microcontroller - a device that includes microprocessor, memory, and I/O signal lines on a single chip, fabricated using VLSI technology.


Microprocessor, CPU & Microcontroller

• In large computers, a CPU implemented on one or more circuit boards performs these computing functions.

• The microprocessor is in many ways similar to the CPU, but includes all the logic circuitry, including the control unit, on one chip.


Traditional block diagram of a computer


Block diagram of a computer with the microprocessor as a CPU


Block diagram of a microcontroller


Basic Concepts of Microprocessors

• Differences between:– Microcomputer – a computer with a

microprocessor as its CPU. Includes memory, I/O etc.

– Microprocessor – silicon chip which includes ALU, register circuits & control circuits

– Microcontroller – silicon chip which includes microprocessor, memory & I/O in a single package.


Arithmetic Logic Unit (ALU)This is the area of microprocessor where various computing functions are performed on data.

Control UnitThe control unit provides necessary timing and control signals to all operating units in the microcomputer. It controls the flow of data between microprocessor, memory and peripherals.

MemoryMemory unit stores group of binary digits (word) that can represent: a. instructions (program) that the computer is to perform. b. the data that are to be operated on by the program.

InputConsists of all of the devices used to take information and data from the external environment to be inputted into the computer system.

Output (I/O)Consists of all of the devices used to transfer information and data from computer system to the external environment.


Definisi Mikrokomputer : Ahli terbaru keluarga komputer, yang mengandungi cip mikropemproses, cip ingatan dan antara mukaan I/O. Dalam beberapa kes,

semua yang disebut berada dalam satu cip tunggal


UNIT CPU (CENTRAL PROCESSING UNIT)

• Satu cip silikon yang bekerja sebagai ‘heart’ komputer.

• Menerima arahan daripada memori utk mengimplementasikan tugas.

UNIT MEMORI • Menyimpan data dan program.

• Terbahagi kepada 2 kategori:


1. MEMORI UTAMA:

1. RAM (Random Access Memory):• Data boleh dibaca dan disimpan.• Data yang disimpan akan hilang apabila

bekalan diputuskan.

2. ROM (Read Only Memory):• Data boleh dibaca tetapi tidak bolehditulis.• Data yang disimpan tidak akan hilang apabila

bekalan diputuskan.

2. MEMORI KEDUA:

• RAM boleh menyimpan data sementara.• Contohnya floppy disc,,harddisk dan CDROM (Compact-disc ROM), yang mana boleh menyimpan kepada 600 million characters dan sesuai untuk menyimpan maklumat yang bersaiz besar.


UNIT INPUT/OUTPUT (I/O):

• Mengandungi litar antaramuka yang diperlukan untuk membenarkan persisian dihubungkan komponen lain.

• Contoh litar antaramuka ialah cip-cip LSI direka oleh pengeluar MPU untuk mengantaramuka MPU ke pelbagai komponen input/output.

• Contoh litar antaramuka yang mudah ialah daftar ‘buffer’.

• Unit I/O membenarkan pengguna untuk berkomunikasi dengan sistem komputer melalui antaramuka untuk berkomunikasi dengan komponen persisian.

• Contoh persisian ialah keyboard, printer dan sensor

• Saiz port input/output ialah sama dengan saiz bas data mikropemproses.


TAHUN SYARIKAT INOVASI

1971 Intel 4004 - P 4 bit pertama: ingatan 1K

1972 Intel 8008 - P 8 bit pertama: ingatan 16K

1974 Intel 8080 - P 8 bit serbaguna pertama: ingatan 64K

Motorola 6800 - P 8 bit pertama drp motorola

1975 MOS 6502 - P 8 bit yg diguna dlm Apple/ komputer pertama

Zilog Z80 - P 8 bit serasi 8080

1976 Intel 8086 - P 16 bit ; ingatan 1M

1978 Intel 8086 – P 16/32 bit ; diguna dlm Apple Macintosh

1980 Intel 8088 – 8086 dgn bas data bit ; diguna dlm IBM PC

1982 Intel 80286 - 8086 dgn ingatan maya ; ingatan 16M

Motorola 68008 – 68000 dgn bas 8 bit ; ingatan 16M

1983 Motorola 68010 - 68000 dgn ingatan maya

1984 Motorola 68020 - P 32 bit ; ingatan 4G

1985 Intel 80386 – P 32 bit

1987 Motorola 68030 – 68020 dgn unit pengurusan ingatan (MMU)

1989 Intel 80486 – 80386 yg lebih laju; unit titik-apung (FPU) bina dlm


TAHUN SYARIKAT INOVASI

Motorola 68040 – 68030 yg lebih laju (FPU) bina dlm

1993 Intel Pentium - 80486 yg lebih laju; superskalar; FPU + 2 ALU

Motorola/IBM/

Apple

Power PC – P RISC

1994 Motorola 68060 – 68040 yg lebih laju; superskalar; FPU + 2 ALU

2003 AMD the first 64-bit IA-32 backwards-compatible architecture, AMD64

Intel •x86-64 chips, the 64-bit desktop • Both processors can run 32-bit legacy apps as well as the new 64-bit software. With 64-bit Windows XP, Linux and Mac OS X (to a certain extent) that run 64-bit native

2006 Intel dual-core processors are widely used in high-end servers and workstations while quad-core processors for servers are beginning to become available.

http://en.wikipedia.org/wiki/Windows_XP_Professional_x64_Edition

http://en.wikipedia.org/wiki/Linux

http://en.wikipedia.org/wiki/Mac_OS_X


DATA SIZE(N)

DATA TYPESDATA CAPASITY

2N RANGE

1 Bit 2 0 – 1

4 Nibble 16 0 - 15

8 Byte 256 0 – 255

16 Word 65536 0 – 65535

32 Long Word 4,294,967,296 0 - 4,294,967,295


FETCH AND EXECUTE CYCLES

1: Microprocessor fetch instruction representing the signal carried by the address bus.

2: Microprocessor execute the instruction.

3) Microprocessor continue the next instruction.

START

Fetch (next) Instruction

Execute Instruction

Is it a HALT instruction?

END

YES

NO


KITAR AMBIL (FETCH CYCLE)uP Meletakkan alamat byte pertama

suruhan pada bas alamat dgn isyarat kawalan, BACA dari lokasi ingatan yg dialamatkan

(Contoh: alamat untuk byte pertama 0FF01H)

uP Mengambil byte dari bas data. Byte ini dinamakan opkod.

Opkod Dinyahkod dan isyarat yang perlu akan dijanakan.


KITAR LAKSANA (EXECUTE CYCLE)

uP akan melaksanakan operasi yang diminta oleh suruhan.


The 8085 Hardware/Programming Model

• A model is a conceptual representation of a real object.

• The microprocessor can be represented in terms of its hardware (physical electronic components) and a programming model (information needed to write programs).


8085 Hardware Model


8085 Hardware Model

• Two major segments:– One segment includes the arithmetic/logic unit (ALU)

and an 8-bit register called an accumulator, instruction decoder, and flags.

– The second segment shows 8-bit and 16-bit registers.– Both segments are connected with various internal

connections called an internal bus. – The arithmetic and logical operations are performed in

the ALU. Results are stored in the accumulator, and flip-flops, called flags, are set or reset to reflect the results


ALUREGISTERSECTION

CONTROL UNITAND

TIMING SECTION

MICROPROCESSOR


Arithmetic Logic Unit (ALU) section:

• Performs variety of arithmetic andlogic operations on data, such as addition, subtraction, AND, OR, EX-OR, shifting, incrementing, and decrementing.

• The more advanced MPU have ALUs that can do multiplication and divisions.


The 8085 Programmable Register


Registers section:

• These internal registers serve as temporary data storage, before, in progress and after the process done by ALU. Data transfer within these registers is much faster as compared to the memory.

• This section contains various registers (inside the MPU), each of which performs a special function.

• These registers are: general purpose registers array, accumulator, instruction register, program counter, and flag register.


Accumulator

• The accumulator is an 8-bit register that is part of the arithmetic/logic unit (ALU).

• This register is used to store 8-bit data and to perform arithmetic and logical operations.

• The result of an operation is stored in the accumulator.

• The accumulator is also identified as register A.


Flags

• The following flags are set or reset after the execution of an arithmetic or logic operation; data copy instructions do not affect any flags. See the instruction set (Appendix F) to find how flags are affected by an instruction.– Z-Zero: The Zero flag is set to 1 when the result is zero; otherwise it

is reset.– CY - Carry: If an arithmetic operation results in a carry, the CY flag

is set; otherwise it is reset.– S - Sign: The Sign flag is set if bit D7 of the result = 1; otherwise it is

reset.– P - Parity: If the result has an even number of 1s, the flag is set; for

an odd number of 1s, the flag is reset.– AC - Auxiliary Carry: In an arithmetic operation, when a carry is

generated by digit D3 and passed to digit D4, the AC flag is set. This flag is used internally for BCD (binary-coded decimal) operations; there is no Jump instruction associated with this flag.


Flag

Block Diagram

D7 D6 D5 D4 D3 D2 D1 D0

S Z X AC X P X CY


ExampleInstruction: ADD B

Register contents before instruction

9A h

89 h

A

B

80 hFlag

Register contents after instruction:

23 h

89 h

A

B

10 hFlag

1 0 0 1 1 0 1 0

1 0 0 0 1 0 0 1

0 0 1 0 0 0 1 1

Note: All flags are modified to reflect the result of the addition.

Flag: S=0, Z=0, AC=1 , P=0 and C=1,


1. Carry (CY) i) C = 1, bendera carry disetkan oleh MSB setelah operasi dijalankan.

ii) C = 1 , Pinjam = 1 apabila terdapat pinjam pada MSB

2. Zero (Z) Z = 1, disetkan apabila keluaran adalah zero,

Z = 0, disetkan apabila keluaran adalah tidak zero,

MSB: b7 b8 = 1 C = 1

E E+ 7 01 5 E

1 1 1 0 1 1 1 0 + 0 1 1 1 0 0 0 01 0 1 0 1 1 1 1 0

b71

b81 1

OperationMSB ……………..……..LSB 000100000000000000

Non-Zero


Z = 0

Z = 0Non-Zero


Zero Z = 1

1011 0101

- 1100 1100

---------------

Borrow 1 1110 1001


3. Sign (S) S = 1, disetkan, apabila keluaran negatif.

S = 0, disetkan, apabila keluaran positif.

Bendera S disetkan dgn melihat pada MSB keluaran.

4. Auxiliary Carry

Bendera ini akan disetkan apabila berlaku ‘carry’ dari bit-3 ke bit-4 semasa operasi campur atau tolak. Bendera ini biasanya akan digunakan dalam operasi aritmetik BCD (binary Coded Decimal)

Operasi: 2F16 00101111

+ 3816 00111000

6716 01100111

OperationMSB ……..……..LSB 1xxx.….xxxx

MSB =1 -ve S = 1

OperationMSB ……..……..LSB 0xxx…..xxxxx

MSB =0 +ve S = 0


5. Pariti (P) Bendera pariti menunjukkan bilangan bit 1 yang ada dalam daftar penumpuk sahaja. Jika

P =1 (ganjil)

P = 0 (genap)

Operasi: 9C16 10011100

4216 01000010

DE16 11011110

Bil. Bit adalah enam maka iaiti genap,P =0


General-purpose Registers

• The 8085 has six general-purpose registers to store 8-hit data; – B, C, D, E, H, and L.

• They can be combined as register pairs - BC, DE, and HL - to perform some 16-bit operations.

• The programmer can use these registers to store or copy data into the registers by using data copy instructions.


Program COUNTER (PC) AND STACK POINTER (SP)

• These are two 16-bit registers used to hold memory addresses.

• PC:– The function of the PC is to point to the memory address from

which the next byte is to be fetched. – When a byte (machine code) is being fetched, the program

counter is incremented by one to point to the next memory location.

• SP:– It points to a memory location in R/W memory, called the stack.– The beginning of the stack is defined by loading a 16-bit address

in the stack pointer. – The PC will automatically update when calling to /returning from

Subroutines.


• 16 – Bit Registers– Program Counter

• A pointer to the next instruction to be executed• Contains the 16-bit memory address of the next instruction• Updated after processor has fetched the instruction

• 6-bit register acting as memory pointer• sequences the execution of instructions• PC points to the memory address from which the

next byte is to be fetched.• while a byte being fetched it is incremented by 1 to

point to next memory location.


– Stack Pointer• Stack – an area in memory in which temporary info

is stored• Stack – FILO (First In Last Out) basis• Holds the address of the top of the stack• 16-bit register acting as memory pointer.• SP points to the memory location in R/W memory

(RAM), called the stack.• The beginning of the stack is defined by loading a

16-bit address in the stack pointer (SP).


Control and timing section:

• The main function is to fetch instruction codes from program memory.

• Then decode (interpret) them, to generate into necessary control signals from MPU

• Then to execute the instructions.• This section also generates timing and

control signals (eg. R/W clock), that are needed by external RAM, ROM, and I/O devices.


8085 Hardware Model

• There are three buses: – a 16-bit unidirectional address bus to send out

memory addresses;– an 8-bit bidirectional data bus, and a control

bus to transfer data, and.– the control bus for timing signals.


Bus system

• A wire is used to transfer a signal from one point to another. A group of wires is called bus.

• In the microcomputer system, there are three buses (data, address, and control) to connect the microprocessor (CPU) to each of the devices in the microcomputer system such as memory and I/O devices.

• These buses will carry (sending or receiving) all the information and signals involved in the system operation from one device to another.


DATA BUS• Bidirectional bus, because data can flow to or from the CPU.• The size of data bus is determined by the number of lines (bits)

which is also called data size. • Data size: Size of single cell in the memory. Numbers of bit the CPU can handle at any one time.• Intel 8085 microprocessorhas 8 bits data bus, thus: Data size n = 8 bits, Data lines are labelled Dn : D0, D1, ….. D6, D7• In other words, the CPU can handle, or data bus can transfer 8 bits

data in parallel simultaneously, thus determine the speed of data transfer.

• The same data bus (bits) can be set to either inputs or outputs depending on whether the CPU is performing a read or a write operation respectively.


ADDRESS BUS• Unidirectional bus, because information flows over it in only one

direction, i.e. from CPU to the memory or I/O elements.• The number of address lines (address bus size) determine the

number of memory cells that CPU can handle.• For instance, the Intel 8085 has 16 bits of address bus: n = 16 bits (Size of address bus): • Address bus is labelled An : A0, A1, ….. A14, A15 2n = 216 = 65536:• CPU can handle or address 65536 single cells (each cell has 8 bits

data size) of memory.• In other words, 16 bit address lines can represent 65536 memory

location:• 0 to 65535 locations, addressed as 0000h to FFFFh


CONTROL BUS

• This is the set of signals that is used to synchronize the activities of the separate microcomputer elements.

• Control bus consists some individual lines for sending and some others for receiving signals from CPU, thus control bus is bidirectional.

• For instance, CPU sends control signals (Read/Write) to the memory or I/O devices to tell them either to be set to receive or send data respectively.

• CPU send Control signal : Read Action: CPU receive data

• CPU send Control signal : Write Action: CPU send data


8085 Instruction Set• An instruction is a binary pattern designed

inside a microprocessor to perform a specific function.

• The entire group of instructions, called the instruction set, determines what functions the microprocessor can perform.


Status Register

(Daftar status/

Daftar bendera)

• 8 bit register – shows the status of the microprocessor before/after an operation• S (sign flag), Z (zero flag), AC (auxillary carry flag), P (parity flag) & CY (carry flag)• storan bagi keputusan ujian-ujian tertentu terutama proses aritmetik dan logik• Sign – keputusan operasi logik/aritmetik menyebabkan msb bernilai 1•Zero – keputusan bagi operasi logik/aritmetik adalah 0•Auxillary carry- apabila berlaku dari bit 3 ke bit 4.•Parity- apabila bit 1 adalah genap.


Status Register

• Carry – carry dari bit ke bit 8


Kuiz 1

– Jelaskan maksud istilah-istilah berikut :• Nibble• Byte• Word

– Terangkan fungsi binaan dalam mikropemproses :

• Unit Aritmetik dan Logik• Accumulator• Stack Pointer


CPU executes each machine instruction by performing a fetch/execute cycle.

CPU fetches an opcode byte from memory and decodes it to find out what it is supposed to do.

CPU executes the instruction.

instructions examine or modify memory or input and output (I/O).

After the instruction

is completed, the cycle resumes for the next instruction.


PERLAKSANAAN SURUHAN DALAM MIKROPEMPROSES

5 Bas Data

6 4

7

1

Bas Alamat

2 3

Mikropemproses Ingatan

Daftar Arahan

Penyahkod

Arahan

Pembilang Aturcara

Arahan dan data

Penyahkod Alamat Ingatan

(Memory Address Decoder)


1 Alamat ingatan bagi suruhan pertama diletakkan ke pembilang aturcara

2 Pembilang aturacara akan meletakkan alamat ingatan tersebut ke bas alamat

3 Alamat ingatan kemudiannya dihantar ke ingatan

4 Ingatan menterjemahkan alamat tersebut dan kedudukan ingatan yang dikehendaki dapat dikesan

5 Ingatan akan menghantar suruhan kembali ke mikropemproses melalui talian bas data

6 Suruhan diletakkan di dalam Daftar Arahan dalam mikropemproses.


7 Mikropemproses menterjemah suruhan tersebut sebelum dilaksanakan

8 Pembilang aturcara akan ditokok dan mikropemproses bersedia menerima suruhan seterusnya


Chapter 2

PENGENALAN PENGAWAL MIKRO Introduction to Microcontroller


What is Microcontroller?

• A microcontroller is an integrated chip that is often part of an embedded system. The microcontroller includes a CPU, RAM, ROM, I/O ports, and timers like a standard computer, but because they are designed to execute only a single specific task to control a single system, they are much smaller and simplified so that they can include all the functions required on a single chip.

• A microcontroller differs from a microprocessor, which is a general-purpose chip that is used to create a multi-function computer or device and requires multiple chips to handle various tasks. A microcontroller is meant to be more self-contained and independent, and functions as a tiny, dedicated computer.


DEFINITION C = single- chip microcomputer

• Contains on-chip resources typically used in embedded applications.

• May not requires extra off-chip resources to function.

• Ex: Intel’s 8051, 8096, Motorola M68HC11, PIC 16XX series etc.


C APPLICATIONS

Applications Example

Computing PC, Notebook, laser printer

Communications Wireless phone, cellular phone

Consumer Video games, camera

Cars Engine control

Cards Banking, Touch N Go


Ciri-ciri microcontroller

• Rekabentuk bersifat “All-in-one”

• Ketegapan (Robustness)

• Keperluan Kuasa yang rendah

(Low Power Consumption)


Microcontroller MCS-51 Architecture


The C Unit (MCU) Internally

3 Basic parts

1. Central Processing Unit (CPU)

2. Memory

3. Registers

( they are connected by an internal bus)

Externally 1. It has pins for power

2. Input/output (I/O)

3. Some special signals


CPU

(Unit pemroses pusat)

Controls the operation of the microcontroller

i. ALU

ii. Control

iii. Register

iv. Bus system

The C Unit (MCU)


C SYSTEMBuffers & converter

Condition I/O signal levels if necessary

Bus Data,address and control

• Data = sinals represent instructions and values of different variables, such as temperature

• Address = indicate where data is stored

• Control = signals coordinate microcontroller operation with associated chips.


C SYSTEMClock Circuit • Generates a fixed-frequency signal

that provides timing information for the entire system.• a crystal connected to two pins of the microcontroller

Power Circuit

• converts incoming power such as 115V alternating current (ac) or 12 V direct current (dc) to the nominal 5 V dc required to operate the microcontoller.


The C Unit (MCU) Memory Is where data and program code are stored.

3 types of memory:

• Read-only memory (ROM)

• Random-access memory (RAM)

• Electrically erasable programmable ROM (EEPROM)

(some Cs use EPROM instead of ROM)


The C Unit (MCU)

Registers • are used to handle specialized information

• It is place where CPU works on (modifies) a binary number.

• There are I/O registers and CPU registers


Sistem BasBas Alamat • Kumpulan talian yang

membawa isyarat alamat dari pemproses ke ingatan dan I/O supaya pemproses boleh mencapai lokasi dan port-port yang tertentu.

Bas Data • Kumpulan talian yag membawa data dari pemproses ke ingatan dan port keluaran dari ingatan dan port masukan ke pemproses


Bas Kawalan • Kumpulan talian yang membawa isyarat kawalan untuk proses seperti baca dari RAM dan port, reset dan interrupt pemproses.


Microcontroller MCS-51 Architecture


Feature 8051 8052 8031

ROM (program space in bytes) 4K 8K 0K

RAM (bytes) 128 256 128

Timers 2 3 2

I/O pins 32 32 32

Serial port 1 1 1

Interrupt sources 6 8 6

Comparison of the 8051 Family Members

94

Pin Description of the 8051PDIP/Cerdip

1234567891011121314151617181920

4039383736353433323130292827262524232221

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7RST

(RXD)P3.0(TXD)P3.1

(T0)P3.4(T1)P3.5

XTAL2XTAL1

GND

(INT0)P3.2(INT1)P3.3

(RD)P3.7(WR)P3.6

VccP0.0(AD0)P0.1(AD1)P0.2(AD2)P0.3(AD3)P0.4(AD4)P0.5(AD5)P0.6(AD6)P0.7(AD7)EA/VPPALE/PROGPSENP2.7(A15)P2.6(A14)P2.5(A13)P2.4(A12)P2.3(A11)P2.2(A10)P2.1(A9)P2.0(A8)

8051(8031)

2 4 531


Pins of 8051 （ 1/4）

• Vcc （ pin 40 ）：– Vcc provides supply voltage to the chip.

– The voltage source is +5V.

• GND （ pin 20 ）： ground

• XTAL1 and XTAL2 （ pins 19,18 ）：– These 2 pins provide external clock.

– Way 1 ： using a quartz crystal oscillator

– Way 2 ： using a TTL oscillator

– Example 4-1 shows the relationship between XTAL and the machine cycle.

1


Pins of 8051 （ 2/4）

• RST （ pin 9 ）： reset

– It is an input pin and is active high （ normally low ） .

• The high pulse must be high at least 2 machine cycles.

– It is a power-on reset.

• Upon applying a high pulse to RST, the microcontroller will reset and all values in registers will be lost.

• Reset values of some 8051 registers • Way 1 ： Power-on reset circuit

• Way 2 ： Power-on reset with debounce

2


Pins of 8051 （ 3/4）

• /EA （ pin 31 ）： external access

– There is no on-chip ROM in 8031 and 8032 .

– The /EA pin is connected to GND to indicate the code is stored externally.

– /PSEN ＆ ALE are used for external ROM.

– For 8051, /EA pin is connected to Vcc.

– “/” means active low.

• /PSEN （ pin 29 ）： program store enable

– This is an output pin and is connected to the OE pin of the ROM.

– See Chapter 14.

3


Pins of 8051 （ 4/4）

• ALE （ pin 30 ）： address latch enable

– It is an output pin and is active high.

– 8051 port 0 provides both address and data.

– The ALE pin is used for de-multiplexing the address and data by connecting to the G pin of the 74LS373 latch.

• I/O port pins

– The four ports P0, P1, P2, and P3.

– Each port uses 8 pins.

– All I/O pins are bi-directional.

4


XTAL Connection to 8051

C2

30pF

C1

30pF

XTAL2

XTAL1

GND

• Using a quartz crystal oscillator

• We can observe the frequency on the XTAL2 pin.


XTAL Connection to an External Clock Source

NC

EXTERNALOSCILLATORSIGNAL

XTAL2

XTAL1

GND

• Using a TTL oscillator

• XTAL2 is unconnected.


Example :

Find the machine cycle for(a) XTAL = 11.0592 MHz (b) XTAL = 16 MHz.

Solution:

(a) 11.0592 MHz / 12 = 921.6 kHz; machine cycle = 1 / 921.6 kHz = 1.085 s(b) 16 MHz / 12 = 1.333 MHz; machine cycle = 1 / 1.333 MHz = 0.75 s


RESET Value of Some 8051 Registers:

0000DPTR

0007SP

0000PSW

0000B

0000ACC

0000PC

Reset ValueRegister

RAM are all zero.


Power-On RESET Circuit

30 pF

30 pF

8.2 K

10 uF

+

Vcc

11.0592 MHz

EA/VPPX1

X2

RST

31

19

18

9


Power-On RESET with Debounce

EA/VPPX1

X2RST

Vcc

10 uF

8.2 K

30 pF

9

31


Pins of I/O Port

• The 8051 has four I/O ports

– Port 0 （ pins 32-39 ）： P0 （ P0.0 ～ P0.7 ）– Port 1 （ pins 1-8 ）： P1 （ P1.0 ～ P1.7 ）– Port 2 （ pins 21-28 ）： P2 （ P2.0 ～ P2.7 ）– Port 3 （ pins 10-17 ）： P3 （ P3.0 ～ P3.7 ）– Each port has 8 pins.

• Named P0.X （ X=0,1,...,7 ） , P1.X, P2.X, P3.X

• Ex ： P0.0 is the bit 0 （ LSB ） of P0

• Ex ： P0.7 is the bit 7 （ MSB ） of P0

• These 8 bits form a byte.

• Each port can be used as input or output (bi-direction). 5


Perbezaan Mikropemroses & Pengawal mikro

Mikropemproses Pengawalmikro

IC tunggal tanpa RAM, ROM, atau I/O

terdiri CPU, RAM, ROM dan pengkalan

I/O

Pereka perlu menambahkan

komponen-komponen(RAM,ROM

dan IO) ini secara luaran untuk mikropemproses

berfungsi

Pereka tidak boleh menambahkan ingatan luar atau pengkalan I/O


Pereka sistem boleh menentukan jumlah

RAM, ROM dan pengkalan I/O yg

diperlukan dalam sistem

Pereka sistem tidak boleh menentukan

jumlah RAM, ROM dan pengkalan I/O kerana

ia adalah tetap yg diperlukan dalam

sistem

Biasa digunakan untuk memproses data

Biasa digunakan untuk tujuan kawalan


PENGENALAN KEPADA BAHASA PENGHIMPUN (SET SURUHAN)INTRODUCTION TO ASSEMBLY LANGUANGE

Chapter 3

Thava Kumar A/L Devanayagam 110

DEFINISI BAHASA

• BAHASA ialah satu medium komunikasi di antara dua atau lebih individu atau kumpulan


Language Categories

Three classes of Languages

•High-level languages

•Hide the detail of computer and O.S.

•Platform-independent

•C++,Java and Fortran

•Assembly languages

•Platform-specific

•Backward compatible


•Machine languages

•Contain binary value

•Platform-specific

Language Categories


Penterjemah

JEPUN

MELAYU

KOMUNIKASI ASAS

Compiler

Bahasa Tahap tinggi

Bahasa mesin

Assembler

Bahasa Penghimpun

Bahasa mesin

Tahap Tinggi

Tahap Pertengahan

Tahap Rendah

Pengaturcara

Komputer

SISTEM KOMUNIKASI KOMPUTER

B A H A S A

B A H A S A

P E N T E R J E M A H

PENGGUNAAN BAHASA DALAM SISTEM KOMUNIKASI


Bahasa Tahap Tinggi(Basic, Pascal and C)

Arahan pengaturcaraan dalam english dan sangat mesra kepada pengguna programmers..

Bahasa Tahap Pertengahan (Bahasa penghimpun)

Bahasa Tahap Pertengahan(Bahasa Mesin))

ASSEMBLER (Penghimpun)

COMPILERS(Pengkompil)

Sistem komputer mengimplementasi

Arahan pengaturcara dalam kod binari,difahami terus oleh sistem

komputer

Arahan pengaturcaraan dalam english

seperti ‘abbreviation’ masih tidak mesra kepada pengguna.

Manusia (Programmers)

PERBEZAAN TIGA BAHASA


Compiling and Assembling

• Compiler convert the high-level language to machine code. And assembler convert the assembly language to machine code

• To make sure every statement is valid.

•To generate the object code.

•Linker combines object code with any other required object code.

• stored as in executable file.

•Loader copies the execute file into memory.


8085 Assembly Language Programming

Compiler:• This is a program that translates English-like words, of a high-level

language in the machine• language of a computer.

Interpreter:• An interpreter is a program that translates the English-like

statements of a high-level• language into the machine language of a computer.

Assembler:• A computer program that translates an assembly language program

from mnemonics to the• binary machine code of a computer.


PERBEZAAN BAHASA PENGHIMPUN

BAHASATAHAP TINGGI

KELEBIHAN • Cepatkan penulisan bhs mesin, kod senang ingat atau singkatan kpd pkt mudah yg dikenali mnemonik mengantikan nilai perenambelasan

• Arahan pengaturcaraan dalam english dan sangat mesra kepada pengguna

• Aturcara mudah ditulis dan mudah dialihkan ke sebarang mikropemproses lain jika perlu.

KEKURANGAN • Arahan pengaturcaraan dalam english seperti ‘abbreviation’ masih tidak mesra kepada pengguna.

• Kod objek yg dihasilkan oleh pengkompil bhs thp tinggi selalunya beroperasi dgn lebih perlahan, saiz kod objek yang terhasil juga lebih besar drp kod objek oleh penghimpun.

• Maka, menggunakan ruang yang besar


8085 Assembly Language Programming

Instruction Set:• An entire group of instructions.

Assembly Language Program:• A set of instructions written in mnemonics of a given microprocessor such as 8085, 8086 etc.

Mnemonic:• A combination of letters to suggest the operation of an instructions (Mnemonic = mindful)

Machine Language:• The binary medium communication with a computer through a designed set of instructions• specific to each computer.• Ex- 1000 0000 ADD B 80H• Instructions in binary form machine lang. Mnemonic Hex codes• This instruction adds the contents of register B to the accumulator.


ALAMAT • Medan yang mewakili setiap baris aturcara bahasa penghimpun dgn lokasi alamat heksadesmal

OPCODE • Medan yang mengandungi kod-kod operasi (heksadesimal) untuk set suruhan 8085 yang telah diterjemahkan dri mnemonik

MNEMONIK • Mengandungi mnemonik suruhan bahasa penghimpun• mnemonik suruhan diterjemahkan menjadi kod mesin yang boleh dilaksanakan pemproses• pengaturcara memasukkan aturcara dgn lebih mudah, tanpa keperluan untuk menghafal nilai-nilai opkod

OPERAND •Sesetengah suruhan memerlukan operand, terdapat suruhan tidak memerlukan operand

KOMEN •Pengaturcara memasukkan penerangan ringkas mengenai setiap baris aturcara, setiap komen mestilah dimulakan dengan simbol (;)

FF01 3E MVI A,1 ;load A with1

Alamat Opcode Mnemonik Operand Komen


•Compilation process for high-level programs.


•Assembly process for assembly programs.


•Compilation process for java programs.


Assembly Language Instructions

1. Instruction formats

2. Instruction Types

• Data Transfer Instructions

• Data Operation Instructions

• Program Control Instructions

3.Data Types

4.Addressing Modes

Instruction Formats Thava Kumar A/L Devanayagam 124

Instruction Formats

Three-operand instructionThree-operand instruction

- the op code and three operands.

Two-operand instructionTwo-operand instruction

-the first operand is both destination and one of the source register.

Instruction Formats Thava Kumar A/L Devanayagam 125

Instruction Formats

One-operand instructionOne-operand instruction

- the accumulator register is always the destination and one of the source register.

Zero-operand instructionZero-operand instruction

- all operands are drawn from the stack.


Instruction Types

Data Transfer InstructionsData Transfer Instructions

-Move data from one place to another

• Load data from memory into the microprocessor.

• Store data from the microprocessor into memory.

• Move data within the microprocessor

• Input data to the microprocessor

• Output data from the microprocessor.


Data Transfer Instructions

• The data transfer instructions ‘copy’ data from a source into a destination without modifying the contents of the source.

• The previous contents of the destination are replaced by the contents of the source.



• Immediate data transfer• Direct data transfer• Indirect data transfer• Register data transfer• Stack data transfer• Illustrative Programs


Immediate Data Transfer Instructions

The memory location, which is indirectly addressed by the HL register pair, appears as the letter M in all instructions.


Immediate Data Transfer Instructions


Direct Data Transfer Instructions

• Direct data transfer instructions are useful if only one byte or word of data is transferred to or from the memory.

• If more than one byte or word is transferred, it is more efficient to use indirectly addressed instruction.



Copies the contents of location 1000H into the L register and the contents of location 1001 H into

the H register

stores the contents of the L register at memory location I200H and the H register at location 1201H


INDIRECT DATA TRANSFER INSTRUCTIONS

• With register indirect addressing, a register pair holds the address of the memory location accessed by the instruction.

• The contents of the register pair indirectly addresses a memory location.

• Whenever, the letter M appears instead of a register, the HL register pair indirectly addresses a memory location.


REGISTER DATA TRANSFER INSTRUCTIONS


STACK DATA TRANSFER INSTRUCTIONS

• The Intel 8085A microprocessor has a LIFO (last-in, first-out) stack memory.

• The stack memory stores both return addresses from subroutines and data temporarily.

• The microprocessor cannot locate the stack memory when power is first applied to the system because the number in the SP is unknown.

• The location of the stack must be initialised after the application of system power.



• The programmer decides what portion of the read/write memory is to function as the stack, and then loads the SP with the top location plus one byte.

• The byte location above the stack is never used, but must be the initial value of the stack pointer.

• The SP always points to the current exit point. • The stack is a LIFO stack.



• If data are pushed (placed) onto the stack, they move into the memory locations addressed by SP-1 and SP-2.

– Note that pairs of registers always move to the stack.

– A PUSH instruction stores the high-order register first (SP - 1), followed by the low-order register (SP -2).

– The SP then decrements by two so that the next push occurs below the first.

– Notice that when the PUSH occurs, nothing is placed at the location addressed by the stack pointer.

– This is why the SP is initialised at one byte above the top of the stack.


STACK DATA TRANSFER INSTRUCTIONS • It is also important to note that PUSHes and POPs must occur

in pairs:

– one PUSH, one POP,

– two PUSHes, two POPs, and so on.

Note: POP PSW will copy the data from location pointed by SP into flag register and data from (SP+1) will copy into A. The SP=SP+2.


STACK POINTER (PENUNJUK TINDAN)

• Merupakan daftar 16 bit yang terdapat di dalam sistem mikropemproses yang bertanda SP.

• Ia digunakan untuk menunjukkan tempat teratas di dalam kawasan tindanan.

• Ianya betindak sebagai daftar alamat bagi ingatan yang dikhaskan.

• Untuk melaksanakan tindan, ia perlu diisytiharkan di alamat paling bawah RAM.


• Ia juga merupakan suatu kawasan dalam memori (kebiasaannya RAM) di mana data atau alamat akan disimpan semasa mikropemproses melaksanakan salah satu daripada 3 perkara berikut:

i. Semasa mikropemproses melaksanakan arahan PUSH dan POP.

ii. Apabila mikropemroses melaksanakan arahan “jump to subroutine: CALL dan RET)

iii. Bila ada “interrupt” kepada mikropemproses.


TAKRIFAN

(tindanan)

Struktur data diambil dengan turutan berlawanan dengan turutan semasa menyimpan (last-in-first-out LIFO)

GAMBARAJAH BLOK

Plate-1

In Plate-1

Plate-1

In Plate-2

Plate-2

Plate-1

In Plate-6

Plate-2

Plate-3

Plate-4

Plate-5

Plate-6

Plate-1

Out Plate-6

Plate-2

Plate-3

Plate-4

Plate-5

Plate-6

Plate-1

Out Plate-5

Plate-2

Plate-1

Out Plate-1

Last In First Out

In Plates

Out Plates

Plate-3

Plate-4

Plate-5


LIFO •Last In First Out•Data yang disimpan (PUSH) kemudian, akan dikeluarkan terdahulu (POP)

FIFO •First In First Out•Data yang mula disimpan (PUSH), akan dikeluarkan (POP) terdahulu.

JENIS-JENIS TINDAN


• Operasi PUSH dan POP dilakukan ke atas kandungan daftar iaitu BC, DE atau HL.

• Suruhan PUSH dan POP tidak akan menyebabkan sebarang perubahan pada daftar bendera/status.

• Suruhan PUSH dan POP adalah suruhan 16 bit (2 byte)• Semasa operasi PUSH, SP akan berkurangan sebanyal

02H dan kandungan pasangan daftar akan disimpan ke dalam tindan.

• Semasa operasi POP, kandungan tindan akan dimuatkan ke dlm pasangan daftar dan penunjuk tindan akan bertambah sebanyak 02H.


• Contoh:

• Suruhan PUSH B bermakna daftar B dan C akan disimpan ke dalam tindan.

• ((SP))-1) <= (B)

• ((SP))-2) <= (C)

• (SP) <= (SP)-2)


• Contoh:

• Suruhan POP D bermakna kandungan tindan dimasukkan ke dalam daftar D dan E

• (E) <= ((SP))

• (D) <= ((SP) + 1)

• (SP) <= (SP) + 2)


FIRST IN FIRST OUT

•MVI B, A6H ;•MVI C, 5AH;•PUSH B ; •POP D; •hlt

FFEE 5A C

FFEF A6 B

FFF0

POP

PUSH

FFF0

FFEF 5A E

FFEE A6 D


Illustrative Program: Data Transfer


EXAMPLE 1

• Load the accumulator A with the data byte 82H (the letter H indicates hexadecimal number), and save the data in register B.

Instructions:Instructions: MVI A, 82H, MVI A, 82H, MOV B,AMOV B,A

The first instruction is a 2-byte instruction that loads the accumulator with the data byte 82H, and the second instruction MOV B,A copies the contents of the accumulator in register B without changing the contents of the accumulator.


MISCELLANEOUS DATA TRANSFER INSTRUQTIONS

• Exchange DE with HL (XCHG)– The XCHG instruction exchanges the contents of the HL register

pair with the contents of the DE register pair.

• Load SP from HL (SPHL)– Is a one-byte instruction, copies the contents of the HL register

pair into the SP.

• Exchange HL with Stack Data (XTHL)– This instruction exchanges the contents of the HL pair with the

most recent data on the stack. • Input/Output Data Transfer Instructions

– IN : instruction inputs data from an I/O device into the accumulator. – OUT : sends accumulator data out to an I/O device.


Instruction Types

Data Operation InstructionsData Operation Instructions

-modify their values.

• Arithmetic instructions:add, subtract,multiply, divide, clear.

• floating point Instructions.

• Logic Instructions:AND, OR, XOR,complement.

• Shift Instructions:left shift,right shift,rotate.


Data Operation Instructions

• Arithmetic Instructions – Addition,– subtraction,– increment, – and decrement.


Arithmetic Instructions


ADDITION

• Addition takes several forms in the 8085 microprocessor: – 8-bit binary, – 16-bit binary, – and two-digit binary-coded-decimal (BCE)) addition.

• Binary addition functions with either signed or unsigned numbers;

• BCD addition uses only unsigned numbers.• The instruction set supports additions using

register addressing, register indirect addressing, and immediate addressing, but not direct addressing.


ADDITION


Addition with Carry• Whenever large numbers (numbers wider than 8 bits, or

multiple-byte numbers) are added, the carry must be propagated from one 8-bit segment to the next.


Addition with Carry


Example for addition• Suppose that the DE register pair contains a 16-bit number that we must add to the

number in the BC register pair. To accomplish this multiple-byte addition, add F and C together and then add D and B together with the carry. The add-with-carry instruction uses the carry from the addition of E and C to generate the correct answer when D and B are added.


Example for addition


Sixteen-Bit Addition • The 8085 instruction set does contain special

instructions (DAD) that do 16-bit addition.


BCD Addition • BCD addition is like binary addition except that the numbers range in value only from 0 through 9. • A special instruction allows BCD addition by using the standard binary addition (ADD) instructions.

– The DAA instruction appears after a BCD addition (with a binary add instruction) to correct the BCD result. – The DAA instruction does not convert a binary number to a BCD number.


Example for Sixteen-Bit Addition

• Example 5-6 illustrates the summation of the packed BCD numbers 11 and 19.

• After this addition, the accumulator contains a 2AH, which is not a BCD number:– the answer should be a 30BCD

– The DAA instruction corrects the answer after the addition and provides a 30BCD after the DAA instruction executes.


BCD Addition• The DAA instruction changes the result through the two tests listed by adding a OOH, 06H, 60H, or

66H to the accumulator.– If the least significant half-byte is greater than 9 or if the AC flag = 1, the DAA instruction adds a 06H to the

accumulator.– If the most significant half-byte is greater than 9 or if the C flag bit 1, the DAA instruction adds a 60H to the

accumulator.


Increment• The last form of addition is to increment or add 1.• The increment command is either an 8-bit (INR) increment or a 16-bit (INX) Increment

instruction.• The INR instructions affect all the flags except carry, and the INX instructions affect no flags.


Subtraction• The 8085 supports 8-bit binary subtraction and decrement. • It also supports a subtraction instruction that allows a borrow to be propagated through

additional bytes of a number. • The subtract-with-borrow instruction aids in the subtraction of multiple-byte numbers.


Subtraction• The 8085 performs subtraction by using the

method of 2’s complement. • Subtraction can be performed by using

either:– the instruction SUB to subtract contents of a

source register or – the instruction SUI to subtract an 8-bit number

from contents of the accumulator.– In either case, the accumulator contents are

regarded as minuend (the number from which to subtract).


Subtraction• Various subtraction instructions: register, register indirect, and immediate addressing. • Direct addressing is not allowed for a subtraction.• Each of these instructions affects the flag bits, so they reflect various conditions about the

difference after a subtraction.


Subtraction• The 8085 performs the following steps internally to execute the instruction SUB (or SUI):

– Converts subtrahend (the number to be subtracted) into its 1’s complement.– Adds 1I to 1’s complement to obtain 2’s complement of the subtrahend.– Add 2’s complement to the minuend (the contents of the accumulator).– Complements the Carry flag.


Illustrative Program: Subtraction of Two Numbers

• PROBLEM STATEMENT– Write a program to do the following:

• Load the number 3011 in register B and 3911 in register C.

• Subtract 39H from 3011.• Display the answer at PORT I.



• PROGRAM DESCRIPTION– Registers B and C are loaded with 30H and

39H, respectively. – The instruction MOV A,B copies 30H into the

accumulator (shown as register contents).



To execute the instruction SUB C the microprocessor performs To execute the instruction SUB C the microprocessor performs the following steps internally:the following steps internally:



• PROGRAM DESCRIPTION– The number F7H is a 2’s complement of the

magnitude (39H-30H)=09H.• This ‘Cy’ flag is set, indicating the answer is in 2’s

complement.

– The instruction OUT displays F7 at PORT1.


Subtraction

P= 0 Odd parity


Subtract with Borrow


Example for SubtractionSuppose that the number in the DE pair must be subtracted from the BC pair. The least significant is operated on first. Once the difference of C and E is found, the D register is subtracted from the B register with a borrow. The subtraction with borrow effectively propagates the borrow through the most significant byte of the result.


LOGIC INSTRUCTIONS • Four basic logic functions:

– invert, AND, OR, and exclusive-OR.• Why does a microprocessor instruction set contain logic

instructions? – Logic instructions sometimes replace discrete logic

gates. – Today, program storage costs about of a cent per

byte. – System control software usually requires bit

manipulation — a logic operation.


Inversion (NOT)• The CMA instruction (2FH in machine language), one’s-

complements or inverts the contents of the accumulator.• This operation, which affects none of the flag bits,

causes each bit of the accumulator to be inverted (changed from 1 to 0 or 0 to 1).

• The CMA instruction causes the accumulator to appear as eight inverters (or NOT). – This means that this one-byte instruction replaces eight discrete

inverters if the speed required is not too great. The amount of circuitry replaced by the CMA instruction is 14 of a 7404 TTL hex inverter.


The AND Operation

• The AND instruction, has two separate functions in a microprocessor-based system. – The AND instruction selectively clears bits of the accumulator or

replaces discrete AND gates.

• The AND instruction, functions as eight independent two-input AND gates. This instruction replaces two 7408 quad two-input AND gates.


The AND Operation


The OR Operation• Has two separate functions in a

microprocessor-based system:– It selectively sets bits of the accumulator or– Replaces discrete OR gates.

• The inclusive-OR instruction functions as eight independent two-input OR gates.

• This instruction replaces two 7432 quad two-input OR gates.


The OR Operation


Illustrative Program:

ORing Data from Two Input Ports

• PROBLEM STATEMENT– Two input port with eight switches (each port)

at address 00H and OIH (Figure 6.9) is connected to the microcomputer to control the same appliances and lights from the bedroom as well as from the kitchen.

– Write instructions to turn on the devices from any of the input ports.



ORing Data from Two Input Ports • PROBLEM ANALYSIS

– To turn on the appliances from any one of the input ports, the microprocessor needs to read the switches at both ports and logically OR the switch positions.

– Assume that the switch positions in one input port (located in the bedroom) correspond to the data byte 9lH and the switch positions in the second port (located in the kitchen) correspond to the data byte A8H.

– The person in the bedroom wants to turn on the air conditioner, the radio, and the bedroom light; and the person in the kitchen wants to turn on the air-conditioner, the coffeepot, and the kitchen light.

– By ORing these two data bytes, the MPU can turn ON the necessary appliances.


Exclusive OR (XOR)


ROTATE INSTRUCTIONS


SHIFT INSTRUCTIONS


Instruction Types

Program Control InstructionsProgram Control Instructions

•Jump/branch instruction similar to GOTO

-absolute(always taken)/conditional

•Software interrupts are generated by specific instructions.

•Hardware interrupts are triggered by device outside of the microprocessor.

•Exceptions/traps are triggered by invalid operation,e.g.:dividing by zero.


Branching Instructions• Jump Instructions:• JMP 16-bit• There are some conditional jump instructions• Call and Return:• CALL 16-bit• RET• There are some conditional jump instructions• Restart Instructions:

Machine Control Instructions• HLT• NOP


• the 8085 code to perform this algorithm

MVI A,5MOV B,AXRA A

Loop: ADD BDCR BJNZ LoopSTA 2000

sum=A A=0

total=sumIF i≠n THEN GOTO Loop

sum=sum+i

i=i-1

Branching Instructions


Branching Instructions

• Execution trace of the 8085 loop summation


Control InstructionsControl Instructions

• Allow computers to make decisions and change the flow of the programme based on the results outcome.

• Two main forms:– JUMP instructions:

• Allow programme to jump to any memory locations.

– CALL instructions• Allow a group of instructions (subroutine) to be

reused by the program in many different places.


CONDITIONAL JUMP CONDITIONAL JUMP

• Conditional JUMP instructions:– Allow the programmer or programme to make a choice

based on conditional terms.– A condition is tested by the microprocessor to decide

whether a jump occurs. – The conditions tested by the conditional jumps are the

same conditions held in the flag bits. – The terms are :

• Zero / not zero• Carry set / cleared• Positive / minus• Parity odd / even


CONDITIONAL JUMP INSTRUCTIONS


• A subroutine is a short sequence of instructions that performs a single task.

• One advantage of using a subroutine is a significant savings of memory space.

• Subroutines also simplify the task of writing a program because subroutines only appear in a program once, but are used often.

• CALL instruction allows the programmer to use (link to) a subroutine.

• When the 8O85 executes a CALL instruction, two events occur: – The contents of the PC are pushed onto the stack, and– The program continues at the address stored with the

CALL instruction. The CALL instruction is a combination of the PUSH and the JMP instructions.

SUBROUTINES


SUBROUTINES


SUBROUTINES• The RET(return) instruction returns to the main program at the

instruction that follows the CALL. • This can be accomplished because the address of this

instruction is stored on the stack because the CALL placed it there as a return address.

• The RET command POPs a number from the stack and places it into the program counter.


SUBROUTINESSTACK(before)

CALL COMP

?

?

1000

Note: Let initial SP=1000H

FFFF

STACK

20

05 FFFE

AFTER CALL COMP

REGISTERS

01A

2040PC

FFFESP


Instruction Size1-byte instructions:• Opcode and operand in the same byte.• MOV C,A Opcode= Hex code = 4FH• ADD B

2-byte instructions:• First byte = Opcode; Second byte = Operand;• MVI A,32H Opcode= Hex code = 3EH = 1st byte; 32H = 2nd byte

3-byte instructions:• First byte = Opcode; Second byte = Low order address; Third byte =

High order address• JMP 3035H Opcode= Hex code = C3H = 1st byte; 35H = 2nd byte;

30H = 3rd byte.


Some Important Symbols

• R = 8-85 8-bit registers (A, B, C, D, E, H, L)• M = Memory register (location)• Rs = Register source (A, B, C, D, E, H, L)• Rd = Register destination (A, B, C, D, E, H, L)• Rp = Register pair (BC, DE, HL, SP)• ( ) = Contents of ---• Note: The microprocessor interprets the first

byte as an opcode and after decoding the• opcode it comes to know about the next

operation to be performed.


Chapter 4

MOD-MOD PENGALAMATAN & TEKNIK PENGATURCARAAN Addressing Modes & Programming technique


Definition

The procedure of fetching and sending data between source and destinations is carried out by various addressing approaches


• Microprocessor needs memory address to access data from the memory.

• Assembly language may use several addressing modes to implement this task.


ADDRESSING MODES OF 8085

• There are 5 addressing mode – Register addressing mode– Direct addressing mode– Register Indirect addressing mode– Immediate addressing mode– Implicit addressing mode



• There are three other very important addressing mode which exist in other microprocessors and are not available in 8085. They are– Indirect Addressing mode– Index addressing mode– Relative addressing mode

• However this addressing mode can be realized in 8085 by combinations of instructions



Immediate addressing:Immediate data is transferred to address or register.

Example:

MVI A,20H. Transfer immediate data 20H to accumulator.

Number of bytes:

Either 2 or 3 bytes long.

1st byte is opcode.

2nd byte 8 bit data .

3rd byte higher byte data of 16 bytes.



Register addressing:Data is transferred from one register to other.

Example:

MOV A, C :Transfer data from C register to accumulator.

Number of bytes:

Only 1 byte long.

One byte is opcode.



Direct addressing:• Data is transferred from direct address to other register

or vice-versa.Example:LDA C200H .Transfer contents from C200H to Acc. Number of bytes:These are 3 bytes long.1st byte is opcode.2nd byte lower address.3rd byte higher address.


ADDRESSING MODES OF 8085Indirect addressing: Data is transferred from address pointed by the data

in a register to other register or vice-versa.

Example:

MOV A, M: Move contents from address pointed by M to Acc.

Number of bytes:

These are 3 bytes long.

1st byte is opcode.

2nd byte lower address.

3rd byte higher address.



Implicit addressing:• These doesn’t require any operand. The data is specified

in Opcode itself.

Example:

RAL: Rotate left with carry.

RRC- rotate accumulator content with out carry No.of Bytes:

These are single byte instruction or Opcode only.


Assembly LanguageAssembly Language• Assembly language:

– Assembly language is used for most programming because it is extremely difficult to program a microprocessor in its native, that is hexadecimal machine language.

• Assembler:– An assembler is a program that converts software written in

symbolic machine language (the source programme) into hexadecimal machine language (object programme).

– The primary reason to use assembler is because development and modification are always difficult in machine language.


Assembly LanguageAssembly Language

• The Two-pass Assembler :– Read programme two times.

1. Generate a table of the labels/symbols within the source programme.

2. Develop hexadecimal version of the source programme.

– Allow forward addressing (the software can jump ahead to an instruction in a program).


Assembly Language


• The assembler always assumes that the first instruction of the programme is stored at memory address 0000H unless otherwise directed by the ORG command.

Assembly Language


• Pass One:– The assembler scans the source programme during the

first pass and generates a table of the labels found within the source programme.

– Each entry in the label table contains the label and the address where the label appears in the programme.

– During the first pass the assembler determines the length of each instruction by updating an internal programme counter.

– This internal programme counter allows the assembler to complete the label table by equating each label with the counter.

– Once the label table is complete the second pass begin.

Assembly Language


• Pass Two:– During the second pass of the source programme, the

assembler forms the object programme.– This occurs by referring to the label table for any

labels that appear in the programme and to an instruction table.

– The instruction table contains all the opcodes in both symbolic and machine language forms.

– The tables help convert the source programme into the object programme.

Assembly Language


Assembly Language


• Assembly Language Statement:– Format :

• Label Field.– Contains a symbolic memory address that refers to

the statement in a programme. Labels are optional and must end with a colon in some Intel 8085A ( : ).

– Labels are constructed from alphanumeric characters and must begin with any letter of the alphabet.

Assembly Language


Assembly Language


• Opcode field:– This field must contain opcodes.

• Operand field:– May contain register name, data or labels.

– If more than one of these is present, they must be separated with comma.

– Data must be encoded as decimal, binary, octal, hexadecimal, or ASCII.

– ASCII must appear as one of more letters surrounded by apostrophe.

Assembly Language


• Operand arithmetic operations.

Assembly Language


• Comment field.

– Must begin with semicolon in most 8085 assemblers and may continue to the end of the line only.

– Use asterisk * or semicolon ; if the comment should continue into the next line.

– Example :

Assembly Language


• Assembler pseudo operations.– Directives to the assembler programme that may

or may not generate machine code. – Examples :

• END, DB, DW, DS, ORG, EQU, IF, ENDIF, SET, GLB, EXT, TITLE, SPC.

– All pseudo operations must appear in the opcode field of a statement.

Assembly Language


• Define Byte (DB).

– Defines 8-bit memory data for a programme.

– Multiple one byte data, comma ( , ) as a separator.

Assembly Language


Assembly Language : Example


• Origin (ORG).

– Changes the starting location of the programme to another address besides 0000H.

– Can be used at any place in a programme to change the location of the assembled machine language instructions or data.

Assembly Language


• Define Word (DW).

– Pseudo operation stores a 16-bit number in the memory for use by a programme.

– Defines no only numeric data but also memory addresses and label.

Assembly Language


• Define Storage (DS).

– Reserves space in a programme for variable data.

– Does not place any specific data into the reserved area of memory.

Assembly Language


• Equate (Equ).

– Equates a label to another label or value.

– Note that the EQU statement label does not contain a colon ( : ).

Assembly Language


Assembly Language


Structured Assembly Language Programming

Structured Assembly Language Programming

• What is structured assembly language programming ?– It is a programming methodology that aids

in the development of complicated software with a minimum amount of error.


Flow ChartFlow Chart• Flow chart is a flow design structured

programme to solve the problems. • Flow chart also helps to correct and modify

developed software.• There are symbols to use in designing flow chart

to ease programmer. These symbols consists of following process: – Process, predefined process, input/output, decision,

connector and terminal.

• Table shows examples of symbols to use in flow chart programme.


• Process Symbol:– Shows any type of process in a programme.

• Predefined process:– Usually contains the name of the subroutine or module.

• Input / output symbol:– Whenever data are input to the programme or output from the

programme.– The input / output symbol usually shows the type of data and

the directioin of data flow.• Decision symbol:

– Computer systems’s most capability is ability to make decisions.

– The symbol asks question to determine the direction of programme sequence.

Structured Assembly Language ProgrammingStructured Assembly Language Programming


• Connector:– Eliminates crisscrossed connecting lines in

complicated flowcharts.– Ease in understanding the developed

programme. • Terminal Symbol:

– Programmes all start somewhere and require a symbol to show where they start.

Structured Assembly Language ProgrammingStructured Assembly Language Programming


• Flow chart example: mean calculation of a set of numbers

Flow chartFlow chart


If-Then-Else


• The solution.

If-Then-Else


• Allows process to be executed or repeated until an event occurs.• Whenever this construct appears, the process first executes a task and

then a test checks for a true or a false condition.• The following figures shows the repeat-until-true and repeat-until-false.

Repeat-Until


• Reads the keyboard until a CR (carriage return) is detected.

Repeat-Until: Example


Do-WhileDo-While• Is comparable to the repeat-until except for one basic

difference.– The do-while construct checks the condition and then, if

required, performs the process and repeats the check.– There are two forms: do-while-false and do-while-true.


Do-WhileDo-While


1. DEFINISI MASALAH

• Pengaturcara hendaklah mengetahui tujuan khusus untuk membina aturcara yang hendak dihasilkan iaitu apakah masalah yang hendak diselesaikan.

• Faktor yang perlu diambil kira:

1. Jenis keluaran yang diperlukan

2. Perkakasan yang ada

3. Bahasa pengaturacaraan yang hendak digunakan

4. Kekangan yang ada

2. MEREKEBENTUK LOGIKAL

• Merekabentuk aturcara yang hendak ditulis, sama ada dalam bentuk algoritma atau secara grafik dalam bentuk carta alir.

PENERANGAN LANGKAH-LANGKAH PROGRAM


3. PENGATURCARAAN • Dgn bantuan algoritma dan carta alir, penulis boleh mula menulis aturcara yang diperlukan dengan menggunakan penyunting (text editor) untuk bahasa penghimpun atau secara terus untuk bahasa tahap tinggi.

• Aturcara ini adalah aturcara punca

(source program)• Contoh program :


4. MUAT TURUN (LOADING), MENGUJI (TESTING) & NYAHPEPIJAT (DEBUGGING)

• Penghimpun (assembler) akan menghimpunkan aturcara bahasa penghimpun.

• Penghimpun akan mengeluarkan fail senarai (list file) yang digunakan untuk mencari kesilapan di peringkat ini.

• Bagi bahasa tahap tinggi, pengkompil dan pentafsir akan menyatakan sebarang kesilapan yang telah dilakukan.

• Kesilapan atau error biasanya ralat sintaks iaitu penggunaan bahasa pengaturcaraan yang salah

• Jika tiada ralat, penghimpun akan mengeluarkan fail objek dan fail heksadesimal.

• Jika tiada ralat sintaks, aturcara boleh dijalankan untuk mengesan ralat logikal atau ralat semantik.

• Ralat logikal adalah kesilapan yang menyebabkan aturcara yang tidak berfungsi seperti yang dikehendaki iaitu tidak menepati tujuan yang ditetapkan.


• Contohnya suatu aturcara ditulis untuk mengira markah penilaian pelajar di dalam kelas. Namun, aturcara yang ditulis tidak dapat mengira dengan tepat, maka aturcara ini ada ralat logikal iaitu penggunaan bahasa pengaturcaraan yang betul tetapi fungsinya tidak tepat. Jika ini berlaku, pengaturcara perlu kembali ke langkah yang kedua (merekabentuk logikal) dan mengulangi proses-proses seterusnya hingga aturcara beroperasi seperti yang dikehendaki.

• Proses pencarian ralat ini juga dikenali proses nyahpepijat atau debugging.

• Bg bhs penghimpun, pengujian boleh dilakukan dengan memuat-turunkan (download) aturcara tersebut pada simulator.

5. DOKUMENTASI PROGRAM

• Pengaturcara boleh mencetak aturcara fail punca sebagai dokumentasi dan mencatat komen yang sesuai pada aturcara sebagai panduan kepada pengguna lain.


LOOPINGLOOPING

• The programming technique used to instruct the MPU to repeat task.– Continuous loop– Conditional loop

• Repeat task until certain conditions are met.• Some loop include indexing along with counter.

– Indexing: pointing or referencing objects with sequential numbers, i.e. data in memory are accessed by referencing to their memory locations.


COUNTERCOUNTER

• Counter. – Counter is constructed by

loading a number to any register.

– Then use INR or DCR to increment or decrement the number respectively.

– Loop is used to update counter value and every iteration the number is inspected to check whether the number is at maximum or minimum.


BLOCK DATA TRANSFERS BLOCK DATA TRANSFERS

• In many systems, blocks of information are transferred from one place to another in the microprocessor’s memory.

• Transferring Blocks of Bytes.

• Transferring Blocks of Words.


BLOCK DATA TRANSFERS BLOCK DATA TRANSFERS

• Suppose that a block of 10 bytes of data, beginning at memory location 2080H, is transferred to a block of memory beginning at location 2090H. – The simplest method, is to use the LDA and

STA instruction to transfer each byte. • Long program

– A more efficient way to transfer a block of data uses the programmed-loop and counter.


Flowchart Flowchart

• Flowchart required to transfer a block of bytes from one area of memory to another .


Transfer 10 bytes of data Transfer 10 bytes of data


Chapter 5

SISTEM INGATAN Memory System


SISTEM INGATAN

•Ingatan adalah peranti yang digunakan untuk

menyimpan data dan maklumat. • Merupakan salah satu peranti yang penting didalam

sistem komputer. • Data yang disimpan didalam sistem ingatan berbentuk

nombor perduaan iaitu '0' atau '1'. •Jenis ingatan dalam sistem ingatan ialah ingatan

semikonduktor (separa pengalir) •Ingatan semikonduktor mempunyai masa capaian

yang pendek berbanding dengan jenis ingatan lain. •Sesuai digunakan didalam sistem mikropemproses

untuk operasi kerja pantas


Kategori ingatan

• Data digit boleh disimpan sebagai cas dalam kapasitans dan sejenis ingatan separa pengalir yang penting menggunakan prinsip bagi mendapatkan simpanan ketumpatan tinggi pada aras keperluan kuasa rendah.

• Ingatan utama juga dikenali sebagai ingatan bekerja yang saling bertindak balas dengan CPU.

• Ingatan Bantu adalah mempunyai muatan untuk simpan jumlah data yang banyak tanpa memerlukan kuasa elektrik yang berkelajuan rendah seperti CD,disket.


MEMORI DLM SISTEM KOMPUTER

Arithmetic unit Control Unit

InternalMemory(semiconductor)

Auxiliary mass strorage

(tape, disk, MBM)

UNITALU

UNITKAWALA

N

MEMORI DALAMAN

(semiconductor)

KOMPUTER


PERBEZAAN INGATAN UTAMA

INGATAN KEDUA

Memori Memori dalaman komputer

Memori luaran komputer

Menyimpan Program Boot up (BIOS) • Program dan data tidak dikendalikan oleh CPU, hanya berlaku permindahan bila diperlukan.

• Perisian aplikasi seperti Microsoft Word.

Contoh RAM and ROM •floppy disk

•CD–ROM

•magnetic disk/tape.


MEMORI SEMIKONDUKTOR

ROM RAM

SRAM DRAMPROGRAMABLE

MROM PROM

UVERASABLE

ELECTRICERASABLE

EPROM

EEPROM EAROM

ERASABLE PROGRAMABLE

(RMM)


Nonvolatile Memories• Nonvolatile memories retain value even if powered off.

– Generic name is read-only memory (ROM).– Misleading because some ROMs can be read and modified.

• Types of ROMs– Programmable ROM (PROM)– Erasable programmable ROM (EPROM)– Electrically erasable PROM (EEPROM)– Flash memory

• Firmware– Program stored in a ROM

• Boot time code, BIOS (basic input/ouput system)• graphics cards, disk controllers.


JENIS-JENIS ROM

ROM ( Read Only Memory )

PROM (Programmable Read Only Memory)

EPROM (Erasable Programmable Read Only Memory)

EEPROM (Electrically Erasable Programmable Read Only Memory)


INGATAN BACA SAHAJA (ROM)

• Ingatan untuk tempat simpanan kekal dimana datanya

hanya boleh dibaca sahaja dari lokasi. • Menyimpan satu bit dengan adanya ikatan di antara

talian baris dan talian lajur didalam susunan ingatan. • Data didalam ROM biasanya telah diaturcarakan pada

masa pengilangan ataupun dengan satu kaedah

aturcara sebelum pemasangan litar. • ROM bersifat 'Non-Volotile' (tak meruap) dimana

aturcara ini tidak akan berubah (padam/hilang)

walaupun bekalan kuasa diputuskan. • ROM sesuai digunakan untuk menyimpan data atau

maklumat penting seperti operasian sisitem ( operating

system )


PROM • Kait boleh lakur

Diatur cara • oleh pengguna, tidak bg pengilang

Keburukan • Sekali diaturcara (OTP)• Tidak boleh dipadam atau diatur cara semula

Setiap sambungan

• dibuat dari 1 fius kait nipis yang sedia tersambung oleh pengilang bakar fius bagi menghasilkan data ingatan tersimpan yang dikehendaki:

. Hubungkan alamat pada alamat masukan

. letakkan data yang dikehendaki pada pin data

. Vpp/Vdd pada nilai tinggi (10-30V)

PROM (Programmable ROM)


( Sumber: Sistem Digit: Ronald A. Reis; m/s 631; rajah 11.9)


PERBEZAAN EPROM EEPROMIngatan Baca Yang boleh diaturcara dan

dipadam menggunakan EPROM eraser (didedahkan kepada cahaya ultraviolet selama 12 minit atau dijemur di bawah sinaran matahari selama 1 hari)

Yang boleh diaturcara dan dipadam menggunakan isyarat (denyut) elektrik.Proses hanya 10ms

Pengguna Tidak boleh memilih untuk memadamkan kandungan tertentu sahaja (boleh mempengaruhi bahagian lain)

Boleh memilih lokasi tertentu sahaja untuk dipadamkan tanpa mempengaruhi bahgaian lain.

Kendalian aturcara Mesti dikeluarkan dari litar untuk diaturcara semula

Tidak perlu dikeluarkan dari litar untuk diaturcara

Penggunaan secara meluas

Di dlm makmal pembangunan produk, makmal kajian (research & development) dan dalam penghasilan prototaip.

Di dlm BIOS sistem komputer (basic input/ Output system)


INGATAN CAPAIAN RAWAK (RAM)

• Ingatan untuk tempat simpanan sementara data

sebelum diproses dalam sistem mikropemproses. • RAM bersifat 'Volotile' (meruap) iatu data yang

disimpan didalamnya akan hilang atau rosak

sekiranya bekalan kuasa terganggu/terputus. • Data pada lokasi/alamat ingatan boleh dicapai

secara rawak • Operasi tulis boleh dilakukan berulangkali pada

lokasi/alamat yang sama dan data sebelumnya

terpadam dan data yang baru akan disimpan.


Random-Access Memory (RAM)• Key features

– RAM is packaged as a chip.

– Basic storage unit is a cell (one bit per cell).

– Multiple RAM chips form a memory.

• Static RAM (SRAM)

– Each cell stores bit with a six-transistor circuit.

– Retains value indefinitely, as long as it is kept powered.

– Relatively insensitive to disturbances such as electrical noise.

– Faster and more expensive than DRAM.

• Dynamic RAM (DRAM)

– Each cell stores bit with a capacitor and transistor.

– Value must be refreshed every 10-100 ms.

– Sensitive to disturbances.

– Slower and cheaper than SRAM.


SRAM vs DRAM Summary

Tran. Accessper bit time Persist? Sensitive? Cost Applications

SRAM 6 1X Yes No 100x cache memories

DRAM 1 10X No Yes 1X Main memories,frame buffers


PERBEZAAN RAM STATIK RAM DINAMIK

Sel ingatan terdiri drp

flip-flop kapasitor

Data Yang disimpan tidak akan hilang selagi ada bekalan kuasa

Yang disimpan akan hilang walaupun bekalan kuasa masih ada apabila kapasitor dicas. Oleh itu, data perlu direfresh atau dicas semula pada sela masa tertentu

Ketumpatan Rendah- IC lebih besar Tinggi- (4 kali ganda SRAM). Saiz unitnya lebih ringkas dan boleh dipadatkan di dalam 1 cip

Penggunaan kuasa Tinggi Rendah- (1/6 atau ½ dr kuasa SRAM)



Format Terdapat pelbagai format(1 bit, 1 byte, ½

byte)- ini memudahkan sistem

ingatan dibina dengan pantas

Hanya terdapat dlm 1 format 1 bit

Kos Kos perbit lebih tinggi Kos perbit rendah (1/4 atau 1/5 kos SRAM)

Maklumat disimpan Dlm bentuk bit-bit pada flip-flop

Dalam bentuk cas-cas pada kapasitor

Penggunaan kendalian

Lebih mudah digunakan krn tidak memerlukan litar tambahan

Lebih rumit krn memerlukan litar tambahan utk refreshkan data



Kepantasan Lebih pantas sederhana

Litar Tidak kompleks kompleks


Conventional DRAM Organization• d x w DRAM:

– dw total bits organized as d supercells of size w bits

cols

rows

0 1 2 3

0

1

2

3

internal row buffer

16 x 8 DRAM chip

addr

data

supercell(2,1)

2 bits/

8 bits/

memorycontroller

(to CPU)


Reading DRAM Supercell (2,1)• Step 1(a): Row access strobe (RAS) selects row 2.

cols

rows

RAS = 20 1 2 3

0

1

2

internal row buffer

16 x 8 DRAM chip

3

addr

data

2/

8/

memorycontroller

• Step 1(b): Row 2 copied from DRAM array to row buffer.

Reading DRAM Supercell (2,1)• Step 2(a): Column access strobe (CAS) selects column 1.

internal buffer

cols

rows

0 1 2 3

0

1

2

3

internal row buffer

16 x 8 DRAM chip

CAS = 1

addr

data

2/

8/

memorycontroller

• Step 2(b): Supercell (2,1) copied from buffer to data lines, and eventually back to the CPU.

supercell (2,1)

supercell (2,1)

To CPU


Memory Modules

: supercell (i,j)

64 MB memory moduleconsisting ofeight 8Mx8 DRAMs

addr (row = i, col = j)

Memorycontroller

DRAM 7

DRAM 0

031 78151623243263 394047485556

64-bit doubleword at main memory address A

bits0-7

bits8-15

bits16-23

bits24-31

bits32-39

bits40-47

bits48-55

bits56-63

64-bit doubleword

031 78151623243263 394047485556

64-bit doubleword at main memory address A


Enhanced DRAMs• All enhanced DRAMs are built around the conventional DRAM core.

– Fast page mode DRAM (FPM DRAM)• Access contents of row with [RAS, CAS, CAS, CAS, CAS] instead

of [(RAS,CAS), (RAS,CAS), (RAS,CAS), (RAS,CAS)].– Extended data out DRAM (EDO DRAM)

• Enhanced FPM DRAM with more closely spaced CAS signals.– Synchronous DRAM (SDRAM)

• Driven with rising clock edge instead of asynchronous control signals.

– Double data-rate synchronous DRAM (DDR SDRAM)• Enhancement of SDRAM that uses both clock edges as control

signals.– Video RAM (VRAM)

• Like FPM DRAM, but output is produced by shifting row buffer• Dual ported (allows concurrent reads and writes)


PERBEZAAN ROM RAMData Dibaca sahaja boleh dibaca atau

ditulis.

Penggunaan Digunakan untuk menyimpan aturcara sistem yang telah di tulis secara kekal dan tidak boleh di ubah.

Digunakan bagi menyimpan data secara sementara (ketika CPU memproses).

Jenis ingatan tidak meruap iaitu kandungannya tidak hilang walaupun bekalan kuasa di putuskan.

meruap iaitu kandungannya akan hilang bila bekalan kuasa diputuskan.


Typical Bus Structure Connecting CPU and Memory

• A bus is a collection of parallel wires that carry address, data, and control signals.

• Buses are typically shared by multiple devices.

mainmemory

I/O bridge

bus interface

ALU

register file

CPU chip

system bus memory bus


Memory Read Transaction (1)

• CPU places address F100 on the memory bus.

ALU

register file

bus interface

F1000

F100x

main memoryI/O bridge

A

Load operation: mov M, A



• Main memory reads F100 from the memory bus, retreives word x, and places it on the bus.

ALU

register file

bus interface

x 0

F100x

main memory

A

I/O bridge

Load operation: mov A, M



• CPU read word x from the bus and copies it into register A.

xALU

register file

bus interface x

main memory0

F100

A

I/O bridge

Load operation: mov A , M


Memory Write Transaction (1)

• CPU places address F100 on bus. Main memory reads it and waits for the corresponding data word to arrive.

yALU

register file

bus interface

F100

main memory0

F100

B

I/O bridge

Store operation: mov M, r



• CPU places data word y on the bus.

yALU

register file

bus interface

y

main memory

0

F100

B

I/O bridge




• Main memory read data word y from the bus and stores it at address F100.

yALU

register file

bus interface y

main memory0F100

B

I/O bridge



W/R

A0

A1

A2

PROCESSOR

CONTROL BUS

Address bus

D7 D7D0

D0

RDCS

8X8

A2 A1 A0 Selected location

0 0 0 0th Location

0 0 1 1st Location

0 1 0

0 1 1

1 0 0

1 0 1

1 1 0

1 1 1Data bus


Interconnection between Processor and Memory


(PC) (MAR)

(MAR) (Address bus) Select a particular memory location

Issues RD control signals

Reads instruction present in memory via database

Will be placed in IR

Read Transaction


Instruction present in IR will be decoded by which processor understand what operation it has to perform

Increments the contents of PC by 1, so that it points to the next instruction address

If data required for operation is available in register, it performs the operation

If data is present in memory following sequence is performed


Cont:-

Address of the data

MAR Address bus select memory location where is issued RD signal

Reads data via data bus MDR

From MDR data can be directly routed to ALU or it can be placed in register and then operation can be performed

Results of the operation can be directed towards output device, memory or register

MAR

Write Transaction


KITAR AMBIL • 2 JENIS OPERASI

1. KITAR BACA

2. KITAR TULIS

Cpu hantar isyarat Melalui bas kawalan, jika bas dlm keadaan sibuk, CPU akan berada dlm keadaan tunggu

Bas tidak sibuk CPU akan letakkan alamat arahan pada bas alamat

Alamat dinyahkod/terjemah

Oleh litar dalam memori atau antaramuka input/output

Data pada alamat yg didapati

Ditempatkan pada bas data

KITAR BACA


BAS ALAMAT

BAS KAWALAN

BAS DATA

MEMORI

RAM ROM MPU

12

SIS

TEM

BAS

LANGKAH 1 : BACA PERMINTAANLANGKAH 2 : KIRIM ALAMAT

PERMINTAAN

BAS ALAMAT

BAS KAWALAN

BAS DATA

RAM ROM

43

SIS

TE

M

BA

S

MEMORI

MPU LANGKAH 3 : TERIMA DATALANGKAH 4 : ISYARAT OK

PERMINDAHAN DATA

KITAR BACA


Boleh CPU menghantar data kpd memori atau alat input/output.

Isyarat CPU akan kirim isyarat (meminta utk menulis) pada bas kawalan

Jika bas data tidak sibuk

• Data diletakkan pada bas data, di mana lokasi alamat akan ditempatkan pada bas alamat.

• CPU akan kirim data ke destinasi (alamat yang telah ditetapkan)

KITAR TULIS


Bas Alamat

Bas Kawalan

Bas Data

LANGKAH 1 : PERMINTAAN TULIS

SIS

TE

M

BA

S

RAM ROM

MEMORi

MPU

1

PERMINTAAN

Bas Alamat

Bas kawalan

Bas Data

LANGKAH 2 : KIRIM ALAMATLANGKAH 3 : KIRIM DATALANGKAH 4 : ISYARAT OK

RAM ROM

MEMORi

MPU

4

2

3

KITAR TULIS

PEMINDAHAN DATA

SIS

TE

M

BA

S


JADUAL JULAT PETA MEMORI UTK 64K

KOMPONENKAPASITI (BYTES)

ALAMAT (HEX) JULAT (DECIMAL)

ROM 12K 0000 - 2FFF 0 - 12287

I/O 4K 3000 - 3FFF 12288 - 16383

RAM 16K 4000 - 7FFF 16384 - 32767

Tidak diguna 32K 8000 - FFFF 32768 - 65535

Jumlah 64K 0000 - FFFF 0 - 65535


PRINSIP AMBIL DAN LAKSANA OLEH INGATAN UTAMA

• Prinsip ambil dan laksana oleh ingatan utama yang berantaramuka dengan mikropemproses menggunakan bas data, alamat dan kawalan

• Masa perlaksanaan setiap suruhan dinamakan kitar suruhan. Kitar suruhan terdiri daripada 3 kitar:

a) Kitar pungut (fetch): ambil suruhan daripada ingatan.

b) Kitar Nyahkod (decode): tafsirkan suruhan yang diterima

c) Kitar Laksana (execution) : laksana suruhan


KITAR PUNGUT KITAR LAKSANA


KITAR PUNGUT

• Mikropemproses mengambil satu suruhan dari ingatan dan mengisikannya ke dalam daftar suruhan (instruction register- IR). Daftar ini tidak kelihatan pada pengaturcara tetapi digunakan oleh Unit Kawalan untuk menentukan operasi yang perlu dilaksanakan.


KITAR NYAHKOD

• Mikropemproses akan menentukan jenis suruhan yang terkandung di dalam daftar suruhan.

• Maklumat yang didapati dalam kitar ini diserahkan kepada kitar seterusnya.


KITAR LAKSANA

• Mikropemroses melakukan apa yang disuruh oleh suruhan yang dipungut


Chapter 6

Masukan / Keluaran & PengantaramukaanInput / Output & Interfacing


Sebuah sistem mikropemproses melakukan berbagai tugas atau kerja dari masa ke semasa. Sebagai contoh, menerima data dari peranti masukan, memproses data, menghantar data ke peranti keluaran.

Kawalan operasi ini, khasnya didalam pemindahan data dari atau ke peranti luaran (peranti masukan/keluaran) dilakukan dengan beberapa cara atau kaedah iaitu:

• Perpindahan Terus (Conditional Data Transfer)• Perpindahan Sampukan (Interrupt) • Capaian Pengalamatan Terus (DMA) • Capaian Jabat-Tangan ( Hand-Shaking )

Masukan / Keluaran


1. Pemindahan terus

Peranti I/O Bersedia untuk menerima/memberi data

Tidak perlu Apa-apa isyarat keluaran sblm pemindahan data dilakukan

Pemindahan data Di bawah kawalan aturcara iaitu dgn bantuan arahan khusus spt IN atau OUT

Contoh Penggunaan

Mesin NC (numerical Controller) yang digunakan utk menggerudi. Masukan dalah bentuk kod berangka mudah dan keluaran adalah disambung terus ke penggerak


2. Sampukan

Definisi sampukan

Satu isyarat yang boleh dihantar pada bila-bila masa dan menyebabkan mikropemproses berhenti melakukan kerja untuk melayan isyarat sampukan tersebut.

Konsep Perkakasan (hardware) yang mengizinkan peranti luar utk mendapatkan perhatian mikropemproses

Contoh Apabila kekunci komputer ditekan, mikropemproses akan memaksa operasi dalaman bercabang melompat ke suatu lokasi di mana terdapat satu susunan tatacara utk membaca papan kekunci tsbt.


Jenis sampukan

1. Maskable Interrupt

Isyarat sampukan yand boleh diterima atau tidak oleh mikropemproses bergantung pada keutamaan menjalankan proses.

2. Nonmaskable Interrupt

Isyarat sampukan mesti diterima oleh mikropemproses.

Kebaikan sampukan

1. Utk memastikan alat I/O atau alat persisian menyampuk mikropemproses.

2. Utk mengurangkan masa dan kos dgn cara sampukan terjadi apabila mikropemproses menerima isyarat sampukan.


INTERRUPTS IN 8085

• Interrupt is a process where an external device can get the attention of the microprocessor.

The process starts from the I/O device The process is asynchronous.

• Classification of Interrupts

Interrupts can be classified into two types:• Maskable Interrupts (Can be delayed or Rejected)• Non-Maskable Interrupts (Can not be delayed or

Rejected)


INTERRUPTS IN 8085

Interrupts can also be classified into:• Vectored (the address of the service routine is

hard-wired)• Non-vectored (the address of the service routine

needs to be supplied externally by the device)

• An interrupt is considered to be an emergency signal that may be serviced.

– The Microprocessor may respond to it as soon as possible.


INTERRUPTS IN 8085

• The 8085 has 5 interrupt inputs.• The INTR input.

The INTR input is the only non-vectored interrupt.INTR is mask-able using the EI/DI instruction pair.

RST 5.5, RST 6.5, RST 7.5 are all automatically vectored.• RST 5.5, RST 6.5, and RST 7.5 are all mask-able.

TRAP is the only non-mask-able interrupt in the 8085• TRAP is also automatically vectored.


INTERRUPTS IN 8085• Non vectored interrupts:

• The 8085 recognizes 8 RESTART instructions: RST0 - RST7 . Each of these would send the execution to a predetermined hard-wired memory location:

Restart Instruction

Equivalent to

RST0 CALL 0000H

RST1 CALL 0008H

RST2 CALL 0010H

RST3 CALL 0018H

RST4 CALL 0020H

RST5 CALL 0028H

RST6 CALL 0030H

RST7 CALL 0038H


INTERRUPT PRIORITY

Interrupt name Mask-able Vectored

TRAP No Yes

RST 7.5 Yes Yes

RST 6.5 Yes Yes

RST 5.5 Yes Yes

INTR YES NO


SIM INSTRUCTION ( SET INTERRUPT MASK)

336

SO

DS

DE

XX

XR

7.5

MS

EM

7.5

M6.

5M

5.5

01234567

RST5.5 Mask

RST6.5 MaskRST7.5 Mask

} 0 - Available1 - Masked

Mask Set Enable0 - Ignore bits 0-21 - Set the masks according to bits 0-2

Force RST7.5 Flip Flop to resetNot Used

Enable Serial Data0 - Ignore bit 71 - Send bit 7 to SOD pin

Serial Out Data

•SIM Instruction helps activate a particular interrupt.

•It can also mask a maskable interrupt.


SIM INSTRUCTION

• Example: Set the interrupt masks so that RST5.5 is enabled, RST6.5 is masked, and RST7.5 is enabled.

• First, determine the contents of the accumulator.- Enable 5.5 bit 0 = 0- Disable 6.5 bit 1 = 1- Enable 7.5 bit 2 = 0- Allow setting the masks bit 3 = 1- Don’t reset the flip flop bit 4 = 0- Bit 5 is not used bit 5 = 0- Don’t use serial data bit 6 = 0- Serial data is ignored bit 7 = 0

SD

OS

DE

XX

X

R7.

5M

SE

M7.

5M

6.5

M5.

5

0 1 00000 1

EI ; Enable interrupts including INTRMVI A, 0A ; Prepare the mask to enable RST 7.5, and 5.5, disable 6.5SIM ; Apply the settings RST masks


RIM INSTRUCTIONREAD INTERRUPT MASK

Serial Data In

RST5.5 Interrupt Pending

RST6.5 Interrupt PendingRST7.5 Interrupt Pending

0 - Available1 - Masked

Interrupt EnableValue of the Interrupt EnableFlip Flop

SD

IP

7.5

P6.

5P

5.5

IEM

7.5

M6.

5M

5.5

01234567

RST5.5 Mask

RST6.5 MaskRST7.5 Mask

}

•Using the RIM instruction, it is possible to can read the status of the interrupt lines and find if there are any pending interrupts.•Since the 8085 has five interrupt lines, interrupts may occur during an ISR and remain pending.


3. Capaian Ingatan TerusDefinisi DMA Membenarkan persisian spt pemacu cakera keras

(hard disk drive) memuatkan data secara terus ke dalam ingatan utama tanpa melalui mikropemproses

Perlu Satu perkakasan khas yang dikenali sbg pengawal capaian ingatan terus (DMAC)

DMAC Adalah satu litar bersepadu (IC) khas yang berfungsi spt 1 satu co-processor (pemproses bersama) krn ianya mampu mengambil alih kawalan sistem bas CPU.

Kebaikan DMA

i. Pemindahan data berlaku dgn pantas krn ia tidak perlu melalui mikropemproses. Kadar pemindahan data menggunakan DMA adalah di antara 10-50 Mbyte/sesaat.

ii. Mikropemproses boleh digunakan utk menjalankan fungsi/tugas lain semasa pemindahan data secara DMA dijalankan. INi menjimatkan masa pengguna.


iii. Dapat menghantar byk data dlm blok yang besar

iv. Pemindahan data boleh dilakukan dgn cepat dari satu blok ingatan ke blok ingatan yang lain.

v. Pemindahan data boleh dilakukan dari peranti terus ke ingatan tanpa melalui mikropemproses

Keburukan

DMA

i. Perlu perkakasan tambahan iaitu DMAC untuk memantau pemindahan data antara alat persisian dengan ingatan

ii. Kos perkakasan tinggi

iii. Prestasi CPU akan sedikit terganggu krn penggunaan sistem bas CPU

Contoh DMA

Menghubungkan pemacu cakera liut( floppy disk drive) dan sistem ingatan sekunder lain dgn ingatan utama RAM. IC DMA yang biasa digunakan untuk kawalan pemacu cakera liut ialah 8271. Bg mikropemproses 68000 ialah M68450.


I/O Bus

mainmemory

I/O bridge

bus interface

ALU

register file

CPU chip

system bus memory bus

disk controller

graphicsadapter

USBcontroller

mousekeyboard monitor

disk

I/O bus Expansion slots forother devices suchas network adapters.


Reading a Disk Sector (1)

•

mainmemory

ALU

register file

CPU chip

disk controller

graphicsadapter

USBcontroller


disk

I/O bus

bus interface

CPU initiates a disk read by writing a command, logical block number, and destination memory address to a port (address) associated with disk controller.



mainmemory

ALU

register file

CPU chip

disk controller

graphicsadapter

USBcontroller


disk

I/O bus

bus interface

Disk controller reads the sector and performs a direct memory access (DMA) transfer into main memory.



mainmemory

ALU

register file

CPU chip

disk controller

graphicsadapter

USBcontroller


disk

I/O bus

bus interface

When the DMA transfer completes, the disk controller notifies the CPU with an interrupt (i.e., asserts a special “interrupt” pin on the CPU)


DMA


8257 DMA

• It is a 4 Channel DMA containing 4 individual I/P ,O/P Channels.

CH0,CH1,CH2,CH3

• It is compatible with Intel processors.• The maximum frequency is 3 MHz.It executes 3 cycles:1. DMA read2. DMA write.3. DMA verify.• The external device can terminate DMA Operation


OPERRATING MODES OF 8257

1. Rotating priority mode: Each channel has equal priority. Priority is shifted from one channel to other.

2. Fixed priority mode: Each channel has a fixed priority

and if higher priority channels are busy then smaller priority will get to serve.

3. Extended write mode: This mode is used to interface slower devices to the system.

4. TC stop mode: If this bit is set the channel whose terminal count is reached is disabled.

5. Auto reload mode: If this bit is set data is transferred by channel 2 only. All other channels are not used.


4. Jabat tangan (hand shaking)

Definisi Jabat tangan

Proses tak segerak (asynchronous) di mana penghantar dan penerima bertukar-tukar isyarat untuk memindahkan data.

Operasi i. Mikropemproses memeriksa talian bas, bersedia cari peranti persisian.

ii. Sekiranya ia rendah (tidak sibuk), mikropemproses akan menghantar isyarat strobe (STB) ke peranti persisian. Peranti persisian meletak data di output register dan bersedia bagi memindahkan data.

iii. Mikropemproses membaca data dari bas data. Talian busy/ready (busy)

iv. Mikropemproses menghantar isyarat acknowledge (ACK) ke peranti persisian bagi menghantar data seterusnya.


Teknik memasukkan dan mengeluarkan data dari komputer selari atau siri


SERIAL COMMUNICATION

Serial Communications systems are of three types:Simplex: This is a one way communication.• Only one party can speak.• The other party only hears to the first one but cant

communicate.System A System B

unidirectional

Transmitter Receiver



System A System B

OR

Transmitter/Receiver

Receiver/

Transmitter

Half Duplex: It is a two way communication between two ports provided that only party can communicate at a time.

•When one party stops transmitting the other starts transmitting.

•The first party now acts as a receiver.



OR/AND.

Full Duplex: It is a two way communication between two ports and both parties can communicate at same time.

• Thus here efficient communication can be established.

Transmitter/Receiver

Receiver/

Transmitter.


CIRI-CIRI PENGHANTARAN SELARI

Setiap bit Data mempunyai talian berasingan dan kesemua bit dihantar secara serentak.

Perpindahan data Segerak iaitu sama ada dalam bentuk byte, word atau longword.

Perhantaran

data

Lebih cepat

Kabel Perlu kabel banyak, maka kos tinggi, oleh itu, hanya sesuai untuk jarak dekat < 100 kaki, contoh: sambungan antara komputer ke printer, monitor atau keyboard.

Kaedah peng.

selari

Digunakan bagi penghantaran data di dalam komputer iaitu di antara:

CPU ke peranti I/O secara terus


Keburukan 1. Kos yang tinggi disebabkan banyak wayar dan daftar-daftar

2. Terjana ‘noise’ (gangguan) jika penghantaran selari digunakan di antara komputer dengan peranti persisian.

3. Sukar mengesan talian yang rosak


CIRI-CIRI PENGHANTARAN SIRISetiap bit Data binari akan dihantar satu persatu melalui

satu talian iaitu satu bit setiap masa

Perhantaran

data

Adalah lambat

Kabel Perlu satu kabel banyak, maka kos murah, oleh itu, hanya sesuai untuk jarak jauh < 100 kaki, contoh:mikrokomputer perlu disambung kepada peranti persisian melalui talian telifon.

Kaedah peng.

siri

Digunakan bagi penghantaran data di dalam komputer iaitu di antara:

1. CPU dan memory

2. CPU dan I/O devices

3. Memory dan I/O devices

Keburukan 1. mudah mengesan talian yang rosak


PENGHANTARAN SIRI

Teknik terbahagi 2:

i. Teknik tak segerak Terdapat kod mula dan henti

ii. Teknik segerak Penghantaran blok dalam satu masa


PENGHANTARAN SIRI TAK SEGERAK

I

apabila menggunakan satu bit mula untuk penerima mengenal pasti permulaan aksara dan 1 atau 2 bit berhenti untuk tanda akhiran aksara


PENGHANTARAN SIRI SEGERAK

Apabila berhubung secara segerak alat penerima dan penghantaran disegerakkan oleh clock yang sama fasa dan kelajuannya. Data akan dihantar dalam bentuk blok. Penghantaran data segerak digunakan untuk penghantaran berhalaju tinggi, tanpa lengahan antara setiap elemen aksara.


TRANSMISSION FORMATS

Asynchronous Synchronous

1. It transfers one character at a time.

1. It transfers group of characters at a time.

2. Used for transfer data rates <20KBPS

2. Used for transfer data rates >20KBPS

3. Start and stop bit for each character which forms a frame.

3. No start and stop bit for each character.

4. Two Clocks are used for Tx and Rx

4. Single clock is used for both Tx and Rx.


PERANTARAMUKA

Definisi perantaramuka Mengawal pergerakan data antara komputer dan peranti persisian (peripherals devices) seperti keyboard, printer, switches, display lamps dan plotter

Contoh Perantaramuka Selari

1. PIA (Programmable Interface Adapter)

2. PPI (Programmable Peripheral interface)

3. PIT ( Parallel Interface Timer)

Contoh Perantaramuka Siri 1. UART (Universal asynchronous receiver/transmitter)

2. ACIA (Asynchronous Communication Interface Adapter)


Fungsi UART Menukarkan data selari yang dihasilkan oleh CPU pertama ke bentuk bersiri yang kemudiannya dihantar ke peranti penerima. Data bersiri ini perlu ditukar semula ke selari sebelum dihantar ke CPU kedua

Komponen utama UART

1. Daftar anjakan, menukarkan data selari ke siri dan sebaliknya.

Rajah


Fungsi ACIA Pengkalan data siri di mana ia berfungsi sebagai perantaramuka di antara data siri dan selari

Ciri-ciri ACIA 1. Data masuk adalah siri

2. Data disimpan di dlm daftara data sebelum dihantar serentak secara selari.

Contoh 1. Isyarat dari peranti persisian adalah siri. Oleh krn pergerakan data dalam sistem mikropemproses adalah selari maka isyarat yang masuk ini perlulah ditukar ke bentuk selari sebelum diproses oleh CPU

Data 0 –7 parallel output

7 6 5 4 3 2 1 0Data series input


Fungsi kabel RS232

Kabel penyambungan data bersiri yang digunakan secara meluas bagi menyambungkan peranti persisian dengan komputer.

Ciri-ciri ACIA 1. Mempunyai 20 talian

2. Biasanya hanya sedikit daripada talian-talian ini digunakan

3. Menghubungkan peralatan pengkalan data (DTE – Data terminal equipment) dengan peralatan penamatan litar data (DCE – Data Communication Equipment).

Contoh 1. DCE ialah computer , DTE biasanya modem

Rajah


8085 Memory Interfacing

• Generally µP 8085 can address 64 kB of memory .

• Generally EPROMS are used as program memory and RAM as data memory.

• We can interface Multiple RAMs and EPROMS to single µP .

• Memory interfacing includes 3 steps :

1.Select the chip.

2.Identify register.

3.Enable appropriate buffer.



• Example: Interface 2Kbytes of Memory to 8085 with starting address 8000H.

Initially we realize that 2K memory requires 11 address lines

(2^11=2048). So we use A0-A10 .• Write down A15 –A0

A1514 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1

1

0

0

0

0

0

0

0

0

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

ADD

8000H

87FFH



• Address lines A0-A10 are used to interface memory while A11,A12,A13,A14,A15 are given to 3:8 Decoder to provide an output signal used to select the memory chip CS¯or Chip select input.

• MEMR¯ and MEMW¯are given to RD¯and WR¯pins of Memory chip.

• Data lines D0-D7 are given to D0-D7 pins of the memory chip.

• In this way memory interfacing can be achieved.


8085 Memory Interfacing• The diagram of 2k interfacing is shown below:

A15-A8

LatchAD7-AD0

D7- D0

A7- A0

8085

ALE

IO/MRDWR

2K ByteMemory

Chip

WRRD

CS

A10- A0

A15- A113:8DECODER


8085 Memory Interfacing•In this example we saw that some address lines are used for interfacing while others are for decoding.

•It is called absolute decoding.

•We sometimes don’t requires that many address lines.So we ignore them.But this may lead to shadowing or multiple address.

•This type of decoding is called linear decoding or partial decoding.

•In partial decoding wastage of address takes place but it requires less hardware and cost is also less as compared with absolute one.


8255 PIN DIAGRAMPA0-PA7 I/O Port A Pins

PB0-PB7 I/O Port B Pins

PC0-PC7 I/O Port C Pins

D0-D7 I/O Data Pins

RESET I Reset pin

RD¯ I Read input

WR ¯ I Write input

A0-A1 I Address pins

CS ¯ I Chip select

Vcc , Gnd I +5volt supply


8255 BLOCK DIAGRAM


8255 BLOCK DIAGRAM Data Bus Buffer: It is an 8 bit data buffer used to interface

8255 with 8085. It is connected to D0-D7 bits of 8255. Read/write control logic:It consists of inputs

RD¯,WR¯,A0,A1,CS¯ . RD¯,WR¯ are used for reading and writing on to 8255 and

are connected to MEMR¯,MEMW¯ of 8085 respectively. A0,A1 are Port select signals used to select the particular

port . CS ¯ is used to select the 8255 device . It is controlled by the output of the 3:8 decoder used to

decode the address lines of 8085.


8255 BLOCK DIAGRAM

A1 A0 Selected port

0 0 Port A

0 1 Port B

1 0 Port C

1 1 Control Register

A0,A1 decide the port to be used in 8255.


8255 BLOCK DIAGRAM

Group A and Group B Control: Group A control consists of Port A and Port C upper. Group B control consists of Port A and Port C lower. Each group is controlled through software. They receive commands from the RD¯, WR¯ pins to

allow access to bit pattern of 8085. The bit pattern consists of :

1. Information about which group is operated.

2. Information about mode of Operation.


8255 BLOCK DIAGRAM• PORT A,B:These are bi-directional 8 bit ports each and

are used to interface 8255 with CPU or peripherals.• Port A is controlled by Group A while Port B is

controlled by Group B Control.• PORT C: This is a bi-directional 8 bit port controlled

partially by Group A control and partially by Group B control .

• It is divided into two parts Port C upper and Port C lower each of a nibble.

• It is used mainly for control signals and interfacing with peripherals.


8255 MODES• Mode 0 : Simple I/O

• Any of A, B, CL and CH can be programmed as input or output

• Mode 1: I/O with Handshake• A and B can be used for I/O• C provides the handshake signals

• Mode 2: Bi-directional with handshake• A is bi-directional with C providing handshake signals• B is simple I/O (mode-0) or handshake I/O (mode-1)

• BSR (Bit Set Reset) Mode• Only C is available for bit mode access.• Allows single bit manipulation for control applications


INTERFACING 8085 & 8255• Here 8255 is interfaced in Memory Mapped I/O mode.

Initially we write down the addresses and then interface it .

A15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Port

1 0 0 0 0 X X X X X X X X X 0 0 A

1 0 0 0 0 X X X X X X X X X 0 1 B

1 0 0 0 0 X X X X X X X X X 1 0 C

1 0 0 0 0 X X X X X X X X X 1 1 CW


INTERFACING 8085 & 8255• Thus we get addresses ,considering don’t cares to be zero

asPort A =8000H

Port B =8001H

Port C =8002H

CWR =8003H

• Then,we give A11,A12,A13 pins to A,B,C inputs of Decoder to enable 8255 or Chip Select.

• A15 is logic 1 so it is given to active HIGH G1 pin& A14 ,IO/M ¯ are given to active low G2B ¯,G2A ¯ pins.

• Output from Latch is given as A0,A1 pins to 8255 while D0-D7 are given as data inputs.


INTERFACING 8085 & 8255

82558085 3:8 decoder

74373

(AD0-AD7)

D7-D0

A0-A7

/CS

A0A1

O0O1

O7

A13A12A11

ALE

RD ¯WR ¯

RD¯WR¯

G2A G2B G1

A15

A14

IO/M

A

B

C PA

PB

PC


INTERFACING 8085 & 8255

Example:Take data from 8255 port B.Add FF H .Output result to port A.

MVI A,82H Initialize 8255.

OUT 83H

LDA 81H Take data from port B

ADI FFH Add FF H to data

OUT 80H. OUT Result to port A.

RST1. STOP.


INTERFACING STEPPER MOTOR with 8255


8253 PIT


8253 Features

• Three independent 16 bit counters.• 24 pin Dual in line Package.• Counting facility in Both BCD and Binary modes.• Dc to 2 MHz operating Frequency.• Can be used as a clock generator.


CONTROL WORD

SC1 SC0 RL1 RL0 M2 M1 M0 BCD

D0D7

0 0 Counter0

0 1 Counter1

1 0 Counter2

1 1 ILLEGAL

SC1 SC0 Select counter

0 0 Counter latching

0 1 Read/load LSB

1 0 Read/load MSB

1 1 R/L MSB 1st then LSB.

RL1 RL0 Read/Load


CONTROL WORD

0 0 0 Mode 0

0 0 1 Mode 1

X 1 0 Mode 2

X 1 1 Mode 3

1 0 0 Mode 4

1 0 1 Mode 5

M2 M1 M0

BCD =0 Binary counter

BCD =1 BCD counter


8253 SQUARE WAVE

• Example: Use 8253 as a square wave generator with 1ms period if the input frequency is 1MHz.

• We use counter 0 as a square wave generator and address of counter 0 =10H and control register =13H.

• I/P frequency is 1MHz.So time is 1µsec.• Count value = Required period /Input period = 1ms/1

µsec• =1000(Decimal).• Thus we use 8253 as a decimal counter.


8253 SQUARE WAVE

• Program:

MVI A,37H Initialize counter 0 mode 3

OUT 13H 16 bit count BCD

MVI A,00H Load LSB count to counter 0

OUT 10H

MVI A,10H Load MSB count to counter 0

OUT 10H. • Thus, the output will be a square wave.


MIKROPEMPROSES 16 BIT DAN 32 BIT


MICPROCESSOR 8 BIT

(Intel 8085)

MICPROCESSOR 16 BIT

(Intel 8086)

I byte 2 byte

CPU and ALU architecture are those that are based on

registers, address buses, or data buses of data size

CPU and ALU architecture are those that are based

on registers, address buses, or data buses of

data size

8 bit data bus 16 bit data bus

sistem mikropemproses & pengawalmikro

Documents

quartz crystal

central processing

bahasa tahap

rom dan pengkalan

bit register

arithmetic

assembly language

data transfer