07-04-2011, 10:52 AM
8051.ppt (Size: 3.3 MB / Downloads: 146)
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)