Problems With Pics (A Beginners Tale of Pic Programming)

So PICs seemed the way forward. Easy to program via the parallel port, cheap and work with simple voltage inputs. And even better, lots of widely available programmer schematics on the net. In the end I decided to order a kit (from Magenta Electronics). It's based upon the David Tait 'Quick and Dirty' programmer with a test circuit thrown in. It was published in Everyday Practical Electronics so its a proven design. So I built the kit. Got a test .HEX (program) written by David Tait (compiled for the 16f84 chip and for the test circuit used). Using programming software specifically designed for the programmer hardware I'm using. So all is good, all is simple. Yes? Well.... no.

So I built the circuit as per the plan, got a fresh new 16f84, applied the power, ran the programming software and pressed the reset switch. Come on little LEDs, flash! And...... nothing. Not a sausage. So I got out the multimeter and checked the voltages. All okay. Switches working, all the components the right way round (a basic mistake I know but it happens). Try again..... nothing. Doh.

So I tried a screened cable (perhaps lots of crosstalk on the cable?). Still nothing. I tried a new PIC (no)..... In desperation I tried a different computer (and thus parallel port). No. So then I added two pullup resistors to the input lines. Getting very clever here eh? And...... nothing. So where is the problem?

After writing off to the newsgroups it became apparent that others have had problems with the 'quick and dirty' programmer. One person wrote and said they had got the NOPPP programmer to work perfectly..... Sounds good!