8051 SERIES OF MICROCONTROLLERS

OUTLINESComparison of microprocessors & microcontrollersAdvantages of microcontrollersEmbedded systemsChoose a microcontrollerSpeed, packaging, memory & cost per unitVarious members of 8051 familyVarious manufacturers of 8051

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MICROCONTROLLER VS. MICROPROCESSORS*

EMBEDDED COMPUTING SYSTEMSUse a microprocessor or microcontroller to do one task onlyPrinterPC used for any number of applicationsWord processor, print-server, bank teller terminal, video game player, network server, internet terminalPC contains or is connected to various embedded productsKeyboard, printer, modem, disk controller, sound card, CD-ROM driver, mouseX86 PC embedded applications

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EMBEDDED PRODUCTS USING MICROCONTROLLERSHomeAppliances, intercom, telephones, security systems, garage door openers, answering machines, fax machines, home computers, TVs, cable TV tuner, VCR, camcorder, remote controls, video games, cellular phones, musical instruments, sewing machines, lighting control, paging, camera, pinball machines, toys, exercise equipment

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EMBEDDED PRODUCTS USING MICROCONTROLLERSOfficeTelephones, computers, security systems, fax machines, microwave, copier, laser printer, color printer, paging

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EMBEDDED PRODUCTS USING MICROCONTROLLERSAutoEngine control, air bag, ABS, instrumentation, security system, transmission control, entertainment, climate control, keyless entry

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CHOOSING A MICROCONTROLLERComputing needsSpeed, packaging, power consumption, RAM, ROM, I/O pins, timers, upgrade to high performance or low-power versions, costSoftware development toolsAssembler, debugger, C compiler, emulator, technical supportAvailability & source

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COMPANIES PRODUCING 8051Table 1-2:Some Companies Producing a Member of the 8051 Family

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CompanyWeb SiteIntelwww.intel.com/design/mcs51Atmelwww.atmel.comPhilips/Signeticswww.semiconductors.philips.comSiemenswww.sci.siemens.comDallas Semiconductorwww.dalsemi.com

INSIDE 8051 MICROCONTROLLERIntroduced by Intel in 1981

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PACKAGES*

8051 ARCHITECTURE8051 architecture contains the following:8 bit CPU with registers A and BA Program counter(PC) and data pointer(DPTR) 8 bit program status word(PSW) 8 bit stack pointer Internal ROM of 0(8031) to 4K(8051) Internal RAM of 128 Bytes 4 register banks 00-1f 16 bytes(bit addressable) 20-2f 80 bytes of general purpose data memory 30-7f

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8951 ARCHITECTURE32 I/O pins arranged as four 8 bit ports (P0 P3) 2 16-bit timer/counters: T0 and T1 Full duplex serial data receiver/transmitter: SBUF Control registers: TCON, TMOD, SCON, PCON, IP and IE 2 external and 3 internal interrupt sources Oscillator and clock circuits

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8051 FAMILYTable 1-4:Comparison of 8051 Family Members

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Feature805180528031 ROM (on chip program space in bytes)4K8k 0kRAM (bytes)128256128Timers232I/O pins323232Serial port111Interrupt sources686

AT89C51Compatible with MCS-51 Products 4K Bytes of In-System Reprogrammable Flash Memory Endurance: 1,000 Write/Erase Cycles Fully Static Operation: 0 Hz to 24 MHz Three-Level Program Memory Lock 128 x 8-Bit Internal RAM 32 Programmable I/O Lines Two 16-Bit Timer/Counters Six Interrupt Sources Programmable Serial Channel Low Power Idle and Power Down Modes

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VARIOUS 8051 MICROCONTROLLERS8751 microcontrollerUV-EPROMAT89C51 from Atmel CorporationFlash (erase before write)DS5000 from Dallas SemiconductorNV-RAM (changed one byte at a time), RTC (real-time clock)OTP (one-time-programmable) version of 80518051 family from PhilipsAD, DA, extended I/O, OTP and flash

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89C51 MICROCONTROLLER*

OSCILLATOR CONNECTIONS*

PORT OPERATIONSTotal 4 portsPort 0 may serve as inputs, outputs, or as a low order address and data bus for external memory.Port 1 may be used as input/output port.Port 2 may be used as input/output or high order address byte.Port 3 may be used as an input/output and for some alternate function.

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PORT OPERATIONSPin Alternate use SFRP3.0-RXD Serial data input SBUFP3.1-TXD Serial data output SBUFP3.2-INT0~ Ext. Int. 0 TCON.1P3.3-INT1~ Ext. Int. 1 TCON.3P3.4-T0 Ext. Tim. 0 TMODP3.4-T1 Ext. Tim. 1 TMODP3.6-WR~ Ext. Mem write pulseP3.7-RD~ Ext. Mem Read pulse

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PORT OPERATIONSTo read and write from port:MOV A, P0 or MOV A,80h

- This copies data from port 0 pins to register A.MOV P1, #0a5h or MOV 90h,#0a5h

- This moves a constant number into port1.Moving data to a port changes the port latch, moving data from a port gets data from the port pins.

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