A BRIEF INTRODUCTION TO 8051 MICROCONTROLLER

[seminar class]

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8051 Basic Component
 4K bytes internal ROM
 128 bytes internal RAM
 Four 8-bit I/O ports (P0 - P3).
 Two 16-bit timers/counters
 One serial interface
Other 8051 featurs
 only 1 On chip oscillator (external crystal)
 6 interrupt sources (2 external , 3 internal, Reset)
 64K external code (program) memory(only read)PSEN
 64K external data memory(can be read and write) by RD,WR
 Code memory is selectable by EA (internal or external)
 We may have External memory as data and code
Embedded System (8051 Application)
 What is Embedded System?
 An embedded system is closely integrated with the main system
 It may not interact directly with the environment
 For example – A microcomputer in a car ignition control
 An embedded product uses a microprocessor or microcontroller to do one task only
 There is only one application software that is typically burned into ROM
Examples of Embedded Systems
 Keyboard
 Printer
 video game player
 MP3 music players
 Embedded memories to keep configuration information
 Mobile phone units
 Domestic (home) appliances
 Data switches
 Automotive controls
Three criteria in Choosing a Microcontroller
 meeting the computing needs of the task efficiently and cost effectively
 speed, the amount of ROM and RAM, the number of I/O ports and timers, size, packaging, power consumption
 easy to upgrade
 cost per unit
 availability of software development tools
 assemblers, debuggers, C compilers, emulator, simulator, technical support
 wide availability and reliable sources of the microcontrollers
Comparison of the 8051 Family Members
 ROM type
 8031 no ROM
 80xx mask ROM
 87xx EPROM
 89xx Flash EEPROM
 89xx
 8951
 8952
 8953
 8955
 898252
 891051
 892051
 Example (AT89C51,AT89LV51,AT89S51)
 AT= ATMEL(Manufacture)
 C = CMOS technology
 LV= Low Power(3.0v)