Hi,

as I mentioned, PIC16F877 wishes - in a strange way - a lower value of
pull-up resistor for his data line during programming. I succeeded with 1
kohm instead of 4.7 or 10.

I hope this experience may help you.

Regards,
Imre


On Mon, 29 Nov 1999, Wojciech Zabolotny wrote:

> On Sun, Nov 28, 1999 at 03:10:07PM -0600, Jake Szot wrote:
> > A classmate and I are making a PIC16f877 programmer as a project in one
> > of our courses and we've run into a problem. The PIC will not let us
> > read data (properly) or advance the program counter while in program
> > mode. Here are the steps we go through to program a location:
>
> [snip]
>
> Hi,
> I had a similar problem with programming of PIC16F877.
> It's description may be found at:
> http://www.infosite.com/~jkeyzer/piclist/1999/Aug/1898.html
>
> However in my case the programming of code memory worked correctly, but
> verification of data EEPROM failed (the PIC returned "0" values
> independently on what I've programmed). Up to this time I haven't found
> the solution of this problem, however with this exception the programmer
> works fine...
> If you get any answer to your question, which may be useful to solve mine,
> please Cc it to me...
> --
>                         TIA
>                         Wojciech Zabolotny
>                         http://www.ise.pw.edu.pl/~wzab
>
> http://www.freedos.org  Free DOS for free people!
>
>