After much hair ripping and shouting I decided to double check everything. This is when I realised I had made a 'take it for granted' mistake. Earlier I was convinced that the PIC just wasn't transmitting. I checked with the logic probe and sure enough a pulse on pin 8. What I now realise is that I didn't check the other end. It turns out that the ZIF socket I have has a bad connection on that pin. Aggghhhhh!
So I now have comms back to the PC terminal from the pic. I have disconnected the URM and now emulate this with the PC. Upon switch on I would expect to see
hi Paul,
Programmed a 16F877 with a modified version of your Basic program. it just loops every 500mSec to send 11h,00h,00h,11h and then 22h, 00h, 00h 22h [ no commas].
Look at the RS232 print out on this image.
I will program a second PC as a URM emulator.
E.
Note: the full stops between Bytes is only on the display so its easier to read
I can now emulate the URM with the PC properly and see the proper commands coming back from the pic.
I can also just connect the URM and emulate the pic from the PC.
Connecting it all together is a no go. For some reason when ever I connect the URM the commands from the pic get corrupted. - Possible noise? - but this is even witout the data lines connected.
I tried a seperate PSU and commoned all the 0v and still the same probem.
Progress IS being made although slowly. At least now I know my (our) code works ...... ;-)