At 20:18 1/08/98 +0100, you wrote:
>Has anyone made a programming adaptor for the 17C756 to allow it to be
>programmed using a Picstart plus?  If so, is it just a matter of connecting
>the parrallel programming pins of the PLCC socket to those used by the
>17C42 or is something more complex required?
>
>
>Martin Walton

Hi Martin,

I have not used the PS+ to program the 17C756 so the following has elements
of educated
guess work.

What I can tell you is that there is both  ICSP  and parallel programming
modes for the
17C756. The parallel mode is  the same as for the 17C4x parts and as you
suggested, yes it is
just a matter of connecting the corresponding 17C756-17C4x pins.

I have all the connections listed at:
http://www.pipeline.com.au/users/newfound/adapter.htm
The listing is under the WARP-17 PLUS link.  I cannot see any reason why it
would be
different from the PS+  A 17C4x programming socket is a 17C4x programming
socket, right?

I had a look in the microchip literature but could find nothing to indicate
which programming
mode the PS+ uses. The only thing I could find was reference to a US$199
adapter!!!???

However, looking through the PS+ firmware I have found nothing to indicate
that the 17C756
is programmed using the ISCP mode. It appears to be programmed as a 17C4x
part.

My suggestion is why not "suck it and see." If you have a CERQUAD package
there is
nothing that will harm it if it turns out the PS+ uses ISCP mode
programming. (It might even
work regardless!) A plastic package might get some junk programmed into it
but it could be worth
the risk losing it.

(Hint, tie a data line low with a 1K resistor. make sure you can do a dummy
read (no device fitted) and
have that line read as '0' Now fit a blank 17C756 and read it. If the
adapter is working then that bit will
read as '1'  This is a bit safer than programming  first up.)

Let us know the outcome. At US$199 for the adapter I'm sure there would be
some interest in
a home built solution.

Jim
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Jim Robertson
NEWFOUND ELECTRONICS
Email: newfound@pipeline.com.au
http://www.pipeline.com.au/users/newfound
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