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-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
Of William Bross
Sent: Wednesday, October 13, 2004 4:46 PM
To: 'Microcontroller discussion list - Public.'
Subject: RE: [PIC] Problem Programming PIC16F877A with ICD2


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-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Koebel, Alen
> Sent: Wednesday, October 13, 2004 4:06 PM
> To: 'piclist@mit.edu'
> Subject: [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? _______________________________________________
> http://www.piclist.com
> View/change your membership options at 
> http://mailman.mit.edu/mailman/listinfo/piclis> t
> 


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