embedded systems and its ports
TRANSCRIPT
EMBEDDED PRESENTATION
Prepared by :-Rahul sharma (11ece29)Nitin (11ece25)Piyush gupta (11ece27)Priya (11ece28)
Incharge:_Mr. Naresh TanwarECE department A.C.E.M
contents
1.Embedded system2.Port3.Port types4.Peripheral devices5.Interfacing6.Output devices
Embedded system embedded system means processor is
embedded into that application. We can say that it is a computing device
that does a ‘specific focused job’. examples:air conditioner,VCD player,DVD
player,printer,fax machine,mobile phones.
port
A port is a device to receive the bytes from external
peripheral(s) [or device(s) or processor(s) or controllers] for reading them later using instructions executed on the processor or
to send the bytes to external peripheral or device or processor using instructions
executed on processor
example SI serial interface in 8051 SPI serial peripheral interface in 68HC11 PPI parallel peripheral interface 8255 Ports P0, P1, P2 and P3 in 8051 or PA, PB,
PC and PD in 68HC11 COM1 and COM2 ports in an IBM PC
I/O port types1.Serial input output ports2.Parallel input output ports
Serial I/O ports
Synchronous Serial Input Synchronous Serial Output Asynchronous Serial UART input Asynchronous Serial UART output Both as input and as output, for example,
modem.
Parallel I/O ports Parallel port one bit Input Parallel one bit output Parallel Port multi-bit Input Parallel Port multi-bit Output
For example IF we take pic microcontroller it have five input output ports which are: 1.Port A2.Port B3.Port C4.Port D5.Port E
Pic18f458 (as example) PIC18F458 has totally 40 Pins, A total of
33 pins are set aside for the five ports PORTA , PORTB, PORTC, PORTD and PORTE .
We can use these ports as a INPUT OrOUTPUT ports. The rest of the pins are designated for Vdd (Vcc) , Vss
(GND),OSC1,OSC2,MCLR(reset) and another set of Vdd and Vss
Pins of ports
PORTA 7 pins PORTB 8 pins PORTC 8pins PORTD 8 pins PORTE 3 pins
Block Diagram of I/O Interfacing
Access one port at a time8-bit registers I/O ports are associated with a SFREach port is associated with 3 registers:
PORT / LAT / TRIS
Buffer
Latch
PIC18F452/4520 I/O Ports (1 of 5)
MCU includes five I/O ports PORTA, PORTB, PORTC, PORTD, and PORTE
Ports are multiplexed meaning they can be set up by writing instructions to perform various functions
Interfacing Output Peripherals (1 of 2) Commonly used output peripherals in embedded systems are
LEDs, seven-segment LEDs, and LCDs; the simplest is LED Two ways of connecting LEDs to I/O ports:
LED cathodes are grounded and logic 1 from the I/O port turns on the LEDs - The current is supplied by the I/O port called current sourcing.
LED anodes are connected to the power supply and logic 0 from the I/O port turns on the LEDs - The current is received by the chip called current sinking.
Common Cathode Common Anode
Active high Active low
Interfacing Seven-Segment LEDs as an Output (1 of 4)
Seven-segment LEDs Often used to display BCD numbers (1 through 9) and a few alphabets
A group of eight LEDs physically mounted in the shape of the number eight plus a decimal point as shown in Figure 9-5 (a)
Each LED is called a segment and labeled as ‘a’ through ‘g’.
Interfacing Seven-Segment LEDs as an Output (2 of 4)
Two types of seven-segment LEDs Common anode Common cathode
decimal point
Seven-Segment Chips
ALPHA/NUMERIC C/A DISPLAY
Interfacing Input Peripherals
Commonly used input peripherals in embedded systems are:
1.Push button keys2.Dip switches3.Keyboard4.Mouse5.touchscreen
Output devices1.LCD screen2.Printer3.PC’s4.
Thank you !!!