PICs - resilient little things

Been pulling the hair out trying to sort either a coding or register configuration problem for the last couple of days.

A simple toggle of a pin (16F886, PORTC,4) to change some data displayed on the LCD wouldn't work.

Initially couldn't figure out why a pin was sitting at 5V with nothing connected to it and it's TRIS register set to an input.

Then after correcting that problem and using a new PIC, it still wouldn't work.

Turns out I should have taken a week off from any sort of electronics stuff - in order of stupidity:-

1/ I managed to connect said pin on PIC #1 to the incoming unregulated supply - input pin fried.

2/ Somehow, there occurred a short on the test jig and the PIC was being fed 9.95 V instead of 5V.

So, after giving myself a good smack around the ears and fixing those problems, I confidently sat down and plugged a new PIC in, expecting to see the correct operation of the program - not to be.

3/ I had managed to bend the pin over, so it wasn't actually plugged in to the socket.

Result - 3 PIC's all fed 9.95V - one with a fried input but otherwise still working and two others both working fine - for now - I suspect they will drop dead sooner rather than later.

It's amazing what you can make with 20+ year old process equipment.

I've still got a fully functional 16C84 that I put in it's socket the wrong way round - and it includes my fingerprint melted in the top

The MicroChip logo on my finger has long since vanished though!

Long live PIC Assembler!!

bobledoux said:

Long live PIC Assembler!!

Click to expand...

I'm a big believer that you should learn assembler before anything else, as it forces you to understand the hardware - once relatively competent at that it's easier to move to a high level language. This is also particularly important with many new PIC's, as datasheets and examples are often all in C rather than assembler.

Doggy's note to self #3:
put white-out on or next to pin 0 of the chip/bus & on the header/socket

Dr_Doggy said:

Doggy's note to self #3:
put white-out on or next to pin 0 of the chip/bus & on the header/socket

Click to expand...

Yep, have started doing that myself.

I have two versions of my LCD backpack board using a 16F18854. I (stupidly) swapped around the ICP socket on the second revision and subsequently connected boards with the ISP connector the wrong way around. Result, never any damage. I now use the first (non usable) boards for just testing code. I need to start doing the white out thing on one of the boards and a red out thing on the others.

Mike.
Edit, lack of white out could (should) indicate red out.

Mistakes always come in threes . Happy new Year.