At 11:00 AM 3/16/98 +0100, you wrote:
>Shahid Sheikh wrote:
>>
>> Hi all,
>>
>> I just made a propic v4.2 (from TATO Computers) programmer and when I read
>> a blank (new) 12C509JW in it, it gives me 3FFF on all the locations. That
>> is the same stuff I get if there is no pic on the programmer. The
>> programmer seems to be working OK as it turns on and off all the supplies
>> to the pic just fine. All my voltage levels are fairly accurate as well
>> (VPP1=12.98V, VDDprog=4.97V, VDDmax=5.50V and VDDmin=2.54V).
>
>I got the same problem on that programmer.
>The problem I found is on the rising edges of the clock and data lines
>used to program the PIC. Watching at them using a scope I saw a 45 deg
>slope instead of sharp edge (perhaps may PC is too fast :-).
>You should solve the problem REMOVING (or using a lower value) the 470pF
>capacitor from RB7 and RB6 to ground or reducing the pull up resistors
>to the same lines (R7 & R8).
>I did the latter (I used 2.2K) and I am very happy with that programmer.
>
>Try that and let me know.
>
>   Marco
>
>
>----
>Marco DI LEO                  email: m.dileo@sistinf.it
>Sistemi Informativi S.p.A.    tel:   +39 6 50292 300
>V. Elio Vittorini, 129        fax:   +39 6 5015991
>I-00144 Roma
>Italy
>
>
If I may add: I use a 6' cat-5 cable and rj45 plugs on my Propic, no caps,
and no problems on my 133MHz Pentium. I don't know if this helps or I am
just lucky.
John