THE MAGAZINE FOR COMPUTER APPLICATIONS
Circuit Cellar Online offers articles illustrating creative solutions
and unique applications through complete projects, practical
tutorials, and useful design techniques.

AN S-7600A/PIC16F877 JOURNEY

Part 1: Laying Out the Tools
by Fred Eady

Start ı Tooling Up ı Hardware Development Tool ı Software Development Tools ı Selecting a Terminal Emulator ı The Boot Loader ı Add Virtual Paper ı Sources and PDF

SOFTWARE DEVELOPMENT TOOLS

The boot loader code for this project can easily be done using Microchipıs MPLAB alone. MPLAB generates a standard Intel hex file that is processed by the development board control program and passed on as executable code to the PIC16F877 on the development hardware.

The S-7600A/PIC16F877 Internet Engineıs main program also can be fabricated with MPLAB and assembler. Iım going to jump ship and produce all of the code for this project using a PIC C compiler called PCW from Custom Computer Services. PCW is a good PIC C compiler that runs under Windows and ties directly into MPLAB. That means you can write C code and debug it in the MPLAB environment. PCW also allows the inline processing of raw PIC assembler code mixed in with the C statements. This projectıs boot loader code will take advantage of that feature many times.

PCW is actually two products in one. PCB is the 12-bit compiler component, and PCM is the 14-bit compiler product. You can purchase PCB or PCM as separate components or get them both in PCW. In either case, youıll get tight code thatıs clever on the inside and easy for others to read on the outside.

Iıll be honest. I had my doubts about the integrity of the resultant C code because Iım used to total control of a PIC using rudimentary assembler instructions. I spent the better part of a week writing segments of C that I thought the compiler would overdo. To my surprise, the output code was good. There are a few things I wish the PCW product would do automatically, but I overcame those by writing my own little routines when necessary. After I got the hang of what the compiler wanted to get my idea into code, I was on my way to an enjoyable ride on a PIC through C country. The MPLAB interface is seamless, and the PCW C compiler has the necessary bells and whistles to allow me to be creative.

PREVIOUS • NEXT