STUDY OF THE ARIZONA MICROCHIP MICRO CONTROLLERS MOSTEFA GHASSOUL DAMMAM TECHNICAL COLLEGE

What are micro controllers ? They are fully integrated small microcomputers They all have the All integrated on a single chip -Processor -RAM for data memory -ROM (EPROM OR EEPROM ) for program memory -Input/ outputs -Timers/ counters -Serial communication -Parallel communication

Many companies make micro controllers. The most famous ones are: - INTEL - PHILIPS - MOTOROLA - ZILOG - SIEMENS - HITACHI - NATIONAL and the ones we are discussing in this presentation ARIZONA MICROCHIP MICRO CONTROLLERS

There are two architectural techniques used in designing the controllers depending on the management of the bus used for program memory and data memory A-von Neumann architecture B-Harvard architecture

In the first architecture, a single bus is used for both data and instruction access, so both the RAM and flash are mapped in the same address space In contrast, Harvard architecture has a separate program and data memory buses. Microchip has opted for this technology in its design.

Though all data bus width is 8 bits for all the micro controllers categories, the program memory bus width varies from 8 bit word for the 12XXX to 14 bit word width for the 16xxx series to 16 bit word width for the 17xxx series. Several advantages are obtained : 1-Simultaneous access of both data and program memories 2-Single word instruction executed in a single cycle except for the branches ( two instructions) 3- Reduction in memory

From programming point of view, two strategies are adopted: 1- Complex Instruction Set Computer (CISC) each instruction is micro coded into several instructions. 2- Reduced Instruction Set Computer (RISC) This technique is implemented by microchip in building its Micros

Advantages: 1- Execution time very fast where each instruction takes a single cycle 2- Number of instructions very minimal As an example: PIC16Cx5x only 33 instructions Its competitor like Motorola 65 instructions for HC05 and 109 for HC11

The controllers come either in 8 pin package with five pins could be programmed as inputs or outputs Or with 14 input/outputs such as the 16c5x micro controllers

The high range (17cxx on top of having 66 input.outputs), it could address n external memory of 64 Kbytes

Two types of serial communication are possible through the master synchronous serial port (MSSP) Where the controller uses it to communicate with other peripherals or micro controllers. Peripherals such as serial EEPROM, shift registers,display drivers,A/D converters ect -The serial protocol either operate as:serial peripheral interface (SPI) where communication takes place through three pins : A- serial data out (SDO) B- serial data in (SDI) C- serial clock (SCK)

The second serial protocol which is supported is the Inter- Integrated circuit (IIC) designed by Philips It communicate with only two lines: A- SDA for data transfer B- SCL for synchronizing clock.

Another protocol supported by the chip is the USART for synchronous asynchronous receiving transmitting communication

Conclusions: 1-micro controllers are becoming more and more involved in daily life of the people. From house hold like washing machines to industrial control as intelligent sensors using different protocols like the IIC. 2- They are also used in communication systems through modems to transfer data over telephone lines 4- They are use to form adaptive, fuzzy controllers just to name a few. 3- There are efforts used to develop micro controllers based PLC to replace micro processors based PLC.