Post by thread:[PIC] Problem Programming PIC16F877A with ICD2

'[PIC] Problem Programming PIC16F877A with ICD2'

I'm experiencing a problem with maybe 20% of the parts I try. They don't

program successfully in-circuit using Microchip's ICD2. I get single word

errors that are persistent (i.e., they don't go away on subsequent attempts

to program). These same parts program fine with an older ICD. I get the same

result if I wire the programming signals PGC and PGD directly to the pins of

the chip, bypassing what I've normally got hanging on those lines (which is

pretty benign to begin with). The programming voltage is 13.4V from the ICD2

and 13.5V from the ICD. Anyone ever see this before and what can I do about

it?

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Alen,

I had the same problem earlier this year.  I tried all sorts of filter

circuits and other assorted gadgetry but still had just over 20% first

time programming failures.  After about 4 calls to Microchip, a nice,

un-named tech admitted that all the flash chips from the Gresham OR

plant (877A comes from there) will not always program properly at VDD =

5.0 VDC.  He told me that you can't set the VDD parameter on the ICD2

but, if you run your circuit VDD externally from the ICD2 down between

4.0 - 4.5 VDC, the ICD2 will choose the low voltage programming

algorithm.  Programs a little slower than at 5 VDC, but I've had 100%

first time successes.  I also broke down and purchased the PM3 for

production so I can directly control the programming voltages.  Hope

this little tidbit helps.

Bill

> {Original Message removed}
That helps enormously. You saved me all kinds of time, I'm sure, as I was

about to contact Microchip and starting asking those kinds of questions.

It's usually always the circuit, never the chip - but not this time, it

would seem. Thanks a bunch!!

{Original Message removed}