FAST - reprogamming on board

**Matt_Edwards** · 04-28-2012, 01:57 AM

I know very little about PICs.

If were to skip the Solder Sockets and dirrect solder the PICs, can I use a IC Clip to connect my Pickit 3 and reprogram them?

Will the surrounding ccts interfere with the progamming voltages?

**budude** · 04-28-2012, 02:11 AM

Originally Posted by Matt_Edwards

I know very little about PICs.

If were to skip the Solder Sockets and dirrect solder the PICs, can I use a IC Clip to connect my Pickit 3 and reprogram them?

Will the surrounding ccts interfere with the progamming voltages?

They certainly can effect things - especially the ICSPDAT and ICSPCLK lines. I had a circuit where I was using the two lines with tie-ups with pushbuttons attached. The 'ol PICkit didn't like that at all... Luckily mine was on a proto board so I would use the clip to pull the PIC out, program it, then pop it back in. You may want to try your circuit out to make sure it can work first (or not).

**dirknerkle** · 04-28-2012, 10:58 AM

Originally Posted by Matt_Edwards

If were to skip the Solder Sockets and dirrect solder the PICs, can I use a IC Clip to connect my Pickit 3 and reprogram them?

Yes. I connected a spring test clip to my programmer and that's exactly how I reprogram chips -- clip it onto the PIC, flash it and verify it, and it works just great. The only issue you can run into is that depending on the board's design, sometimes a test clip won't fit in the space provided...

**LabRat** · 04-29-2012, 08:31 PM

Just tried this on a FAST (spring clip) and it's refusing to recognize the PIC properly. Keeps getting random device ID's returned from both PICKIT3 and PICKIT2.

Going to pull the PIC and drop it in a cradle now. I suspect that there's intereference on the programming control lines.

**LabRat** · 04-29-2012, 10:44 PM

While I've only got a single sample size to pull from, I woulnd't recommend soldering your PIC directly to the board.
In my (one) case, I had to pull the PIC and put it into a cradle in order to program it.

Also observed, attempting to run the FAST with a programer attached resulted in interference that was clearly visible
to the naked eye. It was PIN 13 from the PIC, and it was effectively being driven high, and thus causing visual artifects.

**Matt_Edwards** · 04-29-2012, 11:47 PM

LR,
Excellent work.
Now if I understood PIC better I would ask if the signal on pin 13 could be re assigned to another unused pin, like 2, 5 or 6?
Cheers

**P. Short** · 04-30-2012, 12:42 AM

Originally Posted by Matt_Edwards

LR,
Excellent work.
Now if I understood PIC better I would ask if the signal on pin 13 could be re assigned to another unused pin, like 2, 5 or 6?
Cheers

With firmware and PCB changes, yes.

**LabRat** · 04-30-2012, 09:22 AM

*if* you were modifying the boards, I would recommend PIN 2, so that you could keep the serial RX line clear *just in case* you wanted to add serial input support in the future (Perhaps DMX control of trigger and fall rate?)

**P. Short** · 04-30-2012, 11:10 AM

The other possibility is to use header/shunts to isolate those pins when you're programming the part. It's less foolproof, but keeps the firmware version count down.