Programmer issues

I built a PIC programmer for in circuit programming. As mentioned earlier in the blog it is the SERPIC programmer. It caused me a headache because it did not work properly. It took me an evening to pinpoint the problem.

I have also built a small PIC target board to test the programmer. It contains a 16F84 and one led. It can be used to send my call sign in Morse code.

After I built it it seemed to work. The SERPIC programming software verifies the program by reading it back. No problem was reported. Nevertheless, the program would not run at all. I used the JDM programmer to read the contents. It looked fine. Then I programmed the PIC using the JDM programmer. Now the software runs fine.After erasing the PIC I was able to program the PIC correctly. The next programming attempt failed.

So it seems necessary to erase the PIC first. This was a surprise to me. I have used a simple programmer (direct connection) and this programming software (spp) for years. Erasing was not needed. At least it was not done explicitly. I changed the batch file to erase first then program. Now it works.

I may not be out of the woods yet. One of my PIC seems to be protected although I did not protect it . Another one is not programmable. Writing fails at the first word. Those processors could be damaged. Or the programmer still has issues . Anyway, now I have a target board that I can program over and over again.

Validation of the programmer was done on an old win98 PC using old programming software. I did this to test the SERPIC programmer in a familiar environment. For the software development I will use different software and a more modern PC.