Microcontrollers
MicroChip PIC16 Series





INTRODUCTION

Microprocessors are integrated chips designed for dedicated purposes. Their emergence has greatly reduced the cost and complexity of application circuits. Most microprocessors require minimal power and supported components to run. The PIC16Cxx series manufactured by MicroChip are some of the easiest and cheapest EEPROMs to program and use.

Personally, I find PICs very useful for my computer-control projects. Once I arrive at the final stage of my project, bugs free, I would simply program a PIC according to my I/O controlling logics. With the programmed PIC taking over, I could make my circuit module more compact and, most importantly, would free my controlling PC for other applications.

Originally I was thinking of writing a tutorial for PIC applications. But after looking around, I found that there are already many literatures on the subject. So instead of reinventing the wheel, I would simply make recommendations and point in the direction for those who are interested in exploring in this area.




PIC16C84

For starters, PIC16C84 is an ideal choice to begin with. PIC16C84 is an 8-bit microcontroller which has 36 bytes of RAM, 64 byes of Data EEPROM memory (electrically erasable), 8-level deep stack, and 13 I/0 pins. Some obvious advantages of PIC16C84 are:

* low cost
* few external components
* low power consumption
* R-C oscillator mode
* only 36 instructions
* flexible 13 I/Os
* simple serial programming scheme

PIC16C84: Programming Specifications






EEPROM Writers

There are many PIC programmers available in the market. As a starting point, I would recommend two according to their distinct features. Both could be set up and running in no time at all. For those who are only interested in programming PICs and would like to stay away from electronic circuits, the PICSTART Development Kits by MicroChip would be by far the best choice. At around US$100, the writer comes with complete softwares and manuals. Operating with a PC compatible host system, the PICSTART-16B1 enables you to quickly and easily develop applications for the PIC16Cxx CMOS microcontroller devices. The MPSAM Assembler, MPSIM Simulator and the Development User's Guide provide instructions and descriptions easy enough to follow even for first-timers.



For those who are cost conscious, I would reccommend the "No Parts" PIC Programmers designed by Michael A. Covington (September 1998 Edition) in Electronics Now . The programmer circuit could not be simpler, made up of a few resistors and capacitors. The programmer works with a PC via its parallel port in a series mode and requires a dual +5V and +12V power supply.



Assembler


There are 2 levels of PIC programming languages. Even for the experts, it is not easy to be conversant with machine codes in hexadecimal form. For most of us, it is more comfortable to work with an assembler which converts English-like readable instructions into machine language understood by microcontrollers. Learning nemonic instructions for the PIC16C84 family is not very hard because there are only 36 commands all together. If you do not have an assmebler, you could download the MPLAB Assembler System from MicroChip for free. It is just a matter of hours to grasp the basic and from then on you could be as good as what you want to be.





Conclusion

EEPROMS offer low-cost, programmable flexibility, maintenance free and compactness in circuit designs. Both the PICSTART and "No Parts" Programmer are excellent tools for programming PICs. Assembler, useful libraries and related softwares are readily available everywhere and free for most. It practically requires no more effort than a few hours' time for anyone to get in touch with the state-of-the-art in microelectornics.

Happy Pic'king!


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