Complex PIC Programmes Made Simple

Complex PIC Programmes Made Simple

Peter Brunning writes his thoughts to help you create bug free PIC programmes (programs)

Over the years that I have been running Brunning Software I have had many interesting conversations with perspective and current customers. Usually the customer will want to talk about his project before making his final decision to purchase our PIC Training and Development System. A common theme that crops up during these conversations is that the customer is planning a project that is unnecessarily complex.

Recently a customer asked me how many analogue inputs the PIC16F877 could successfully convert into digital information. The answer is that all of its 8 analogue inputs can be used. The only problem being that although there 8 analogue inputs there is only one A/D converter. So if all 8 inputs are used the PIC requires 8 times longer to do the conversions meaning that the overall system runs 8 times slower.

When speed is a problem and more than one analogue input is required the programming can become very complex. But there a simple solution. A separate PIC can be used for each input and if necessary another PIC can be used to coordinate the timing and run the main routines.

The 28 pin PIC16F872 and PIC16F870 have the same 10 bit A/D converter (with 5 inputs) as the 40 pin PIC16F877 but cost about half the price.