[SOLVED] PIC18LF1220 - can only program ONCE (ICD-U64)

[newguy]

I have a really weird problem I've never encountered before. A freshly manufactured board I can program, ONCE. If I try to reprogram it, I get verification errors. If I try to erase the chip, the erase operation is successful but if I try to verify that it's blank I get an error - chip NOT blank.

I'm wondering if it doesn't have something to do with the board and what this processor does on it. It's a simple power supply/distribution board. More complex boards stack on it. It takes 28V in, and has three power supplies to create 12.0, 5.0, and 3.3V (each 2A). The processor simply monitors the voltage on each supply and controls 4 LEDs - one for each supply.

The PIC is powered from the 3.3V supply. A precision 2.048V reference is fed to AN0. A resistor divider from the 5, 12, and 28V supplies each feed the AN1-3 inputs. Based on the fact that the AN0 input is fixed, the voltage of the 3.3V supply can be calculated, and the rest of the supplies can then be easily measured.

Only thing I can think of is that the analog voltages are putting the chip into a weird latch-up condition or something like that. There's definitely some sort of interference/whatever which is preventing a full erase.

Any thoughts?

Edit: definitely voltage/programmer related. Load-n-Go works without issue.

[alan]

Hi newguy

It seems that somehow the U64 can only program some chips once> I had the same problem see (http://www.ccsinfo.com/forum/viewtopic.php?t=49444), but the ICD3 works without problems. In the meantime I have used my U64 for other chips so definitely not blown. Must admit I never contacted CCS, maybe now are a good time as it is not only me.

Regards

[newguy]

Glad I'm not the only one. I did send an email to CCS support regarding the issue. 2nd one this week, as I learned Monday that the latest FW release for the Load-n-Go bricks dsPIC33FJ256GP710A's.

[newguy]

UPDATE: version 3.01 of ICD-U64 firmware fixes this issue.

[gpsmikey]

"fixes this issue" - both problems or just one of them ? (there were two issues - one was bricking a chip the other was only able to program a different chip once)

mikey
_________________
mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3

[newguy]

Just this issue. Two different programmers, one issue each. The Load-n-Go dsPIC33FJ issue is still outstanding.

[gpsmikey]

Ah, ok, thanks for the clarification.

mikey
_________________
mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3