controller report

controller report - CHAPTER 4 4. DESCRIPTION OF...

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CHAPTER 4 4. DESCRIPTION OF MICROCONTROLLER Fig 4.1 Block Diagram of Microcontroller INTERNAL LAYOUT OF MICROCONTROLLER CPU INTERRUPT CONTROL OSC ON-CHIP RAM SERIAL PORT 4 I/O PORTS BUS CONTROL ON-CHIP ROM FOR PROGRAM CODE TIMER0 TIMER1 EXTERNAL INTRRUPTS COUNTER INPUTS ADDRESS/DATA TXD RXD P0 P1 P2 P3
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Fig 4.2 Internal Layout of Microcontroller 4.1. DESCRIPTION OF 89C51 MICROCONTROLLER Phillips 89C51 contains a non-volatile FLASH program memory that is parallel
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programmable. Phillips 89C51, 8-bit Micro controller from MHS-51 Intel family, with 4K bytes of flash and 128 bytes of internal RAM had been used. It has a 40-pin configuration and other components of interfaced to its ports. The Micro controller takes input from the external sources and routes them to the appropriate devices as programmed in it. 4.2. FEATURES 89C51 Central Processing Unit On-chip FLASH Program Memory Speedup to 33 MHz Fully Static Operation RAM expandable externally up to 64 Kbytes Four interrupt priority levels Six interrupt sources Four 8-bit input output ports Full-duplex enhanced UART -Framing error detection -Automatic address recognition Three 16-bit timers/counters T0, T1and additional T2 Power control modes -Clock can be stopped and resumed -Idle mode -Power down mode Programmable clock out
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Second DPTR register Asynchronous port reset Low EMI Wakeup from power down by an external interrupt Flash memory features FLASH EPROM internal program memory with chip erases. Up to 64K byte external program memory if the internal program memory is disabled Programmable security bits. 10,000 minimum erase/program cycles for each byte 10 year minimum data retention Programming support available from many popular vendors. CPU The microcontroller consists of eight bit ALU with associated registers like register A, register B, PSW (program status word), SP (stack pointer), and a 16-bit PC (program counter) and a 16-bit DPTR (data pointer) register. ALU The ALU performs arithmetic and logic functions on 8-bit variables. The ALU can perform addition, subtraction, multiplication and division and the logic unit can perform logical operations. An important and unique feature of the microcontroller architecture is that the ALU can also manipulate 1 bit as well as 8-bit data types. Individual bits may be set, cleared, complemented, moved, tested and used in logic computation. ACCUMULATOR It is returned as register A or Acc. It is an 8-bit Register. Accumulator holds a source of operand and stores the result of the arithmetic operations such as addition, subtraction,
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multiplication and division. The accumulator can be the source or destination register for logical operations. The accumulator has several exclusive functions such as rotate, parity computation; testing for 0, sign acceptor etc. and so on. PROGRAM COUNTER
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This note was uploaded on 02/13/2011 for the course EE 426 taught by Professor Dr.c.d.naidu during the Spring '09 term at SUNY Buffalo.

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controller report - CHAPTER 4 4. DESCRIPTION OF...

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