                       TOPIC PROBLEMS
                       --------------

If you haven't done it already remove the PIC from the TOPIC 
board and run DEBUG.BAT (see TOPIC.TXT for a brief description
of what this does).

The program TCHK.EXE checks the timing routines used by TOPIC 
and you don't need to have the TOPIC board connected to try this 
test.  Using a watch with a seconds hand, find the time taken
for TCHK to execute: it should take 20 seconds for the DOS prompt 
to return.  Don't worry if it takes slightly longer but if TCHK
executes in significantly less than 20 seconds (or even worse, 
it doesn't finish at all) it's very unlikely that your PC can be 
used with TOPIC - sorry.

If you have problems getting the programmer to work it's most
likely due to one of two things: 1) using an excessively long
cable to connect the TOPIC hardware to the PC (remedy obvious);
or 2) the assumptions I make about your PC parallel port operation
are wrong.  You can increase the probability that my assumptions
are correct by using the BIOS setup of your PC to make sure it is 
working in Standard Printer Port (SPP) mode and not bidirectional
or ECP/EPP mode.  However, even this might not help much for some PCs.
The assumptions I make are described in TOPICLPT.TXT (in rather 
more detail than you probably want :-).  This file also describes
a couple of mods which you can try.  If the mods don't help, remove
the connections to the SEL and BUSY lines altogether (this means 
you'll not be able to dump/verify the PIC) and use the -n (no
read option) of the TOPIC software, i.e. add -n to the command
line when you use TOPIC.  This will work with virtually all PCs
but there are a few that will still not play ball I'm told.  I have
never come across one of these rogue PCs myself and consequently
don't really know why they don't work.  If you have spent time
building a TOPIC board and find you can't get it to work at all
then I'm really sorry you've wasted your time.

If the programmer seems to work but you can't get the PIC to do
anything make sure you are using the correct configuration word
for your setup.  The file WALK.HEX can be used to check everything 
is OK.  As supplied it can be run on a TOPIC board with a crystal
oscillator installed.

David Tait
6/Jun/1998

