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STUDY OF THE ARIZONA MICROCHIP MICRO CONTROLLERS
MOSTEFA GHASSOUL
DAMMAM TECHNICAL COLLEGE
Email :[email protected]
What are micro controllers ?
They are fully integrated small microcomputers
They all have the
-Processor
-RAM for data memory
-ROM (EPROM OR EEPROM ) for program memory
-Input/ outputs
-Timers/ counters
-Serial communication
-Parallel communication
All integrated on a single chip
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 InterIntegrated 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
3- There are efforts used to develop micro controllers based PLC to
replace micro processors based PLC.
4- They are use to form adaptive, fuzzy controllers just to name a
few.