Introduction

There are countless application in which hardware needs to be intelligent. To save building acres of circuitry using discrete 7400 series logic a PIC microprocessor can be used. These versatile "computers on a chip" from Microchip became popular in the early 1990s and can be found embedded in household objects such as washing machines and VCRs.

PICs contain memory, I/O ports as well as the CPU and are almost always bought in a blank state. They are then loaded with the code from a host computer in a similar way to an EPROM.

Producing code

Having deisgned the hardware in which the PIC will be in embedded you then need to write its software - this is usally written in assembler since PICs use a RISC architecture with just 36 different instructions.

Microchip's first assembler spawned an explosion of assemblers for the IBM compatible PC. However, few exist for use with RISC OS. PICbasic is one such native one. Using it, assembler is written into a normal BBC BASIC file just as you would if you were writing for the BBC or RISC OS. Indeed, the program is so efficient that it can actually be used from a BBC!.

Best of all, PICbasic is available for free. As freeware it should allow you to try out the world of PICs for no cost to you.

PICsuite

PICbasic will produce an object file which is ready to be programmed into the PIC. Where possible, use of an EEPROM based or UV Erasable PROM is recommended - as these allow for rewriting whilst your bugs are being ironed out of your software!

With the commercial package (which includes the actual hardware to program the PIC) you get three more programs:

• PICdis - a disassembler which takes a binary file (as produced by PICbasic) and outputs the assembler part of the file. With the addition of a FOR...NEXT loop this code can be refed into PICbasic to get back your original code.

• PICtracer - this clever software allows you to monitor how your software will behave even before you load it onto a chip.

• PICprog - this program drives the included PIC programmer board and commits your software to the device of your choice. The software includes program/verift/blank check and dump capability. Configuration bits, user ID, EEPROM data memory and, of course, code memory can all be programmed or read and saved in a variety of formats.

• PIClaunch - a graphical front end to drive both the assembler and disassembler.

Ordering details

Comparable products include part VH00A from Maplin Electronics in Essex costing £149.99 or 631-760 from Farnell Electronics in Leeds for £143.94.

PICsuite, however, costs much less (all inclusive):

The "Checkout" link above will take you to a secure page where you can pay by credit or debit card. Alternatively, see this guide for details on how to pay by cheque. Delivery takes approximately three weeks as the boards are manufactured abroad. Any availability questions you may have should be emailed to us. Technical questions can be emailed direct to the author.

Devices supported

The assembler and disassembler understand all of the 12 and 14 bit variants. This includes the tiny 8 pin 12CXXX series which are often embedded into consumer devices such as games machines and satellite decoders.

In addition the programmer driver is capable of handling the micros listed in the following table (some need a simple adapter if physically too big to fit into the on board ZIF socket - full details are supplied on how to build these).

As PIC suite is driven by device 'templates' it is normally only necessary to add additional devices to the list of known PICs. However it is recommended you check with the author first.

© Jaffa Software 2000. All rights reserved.
Last modified: Mon Dec 16 12:23:36 2002