>>Can someone give me a clue how to get this thing to work?
>>Is my PC running too fast for PIP-02?  I have a slower PC at home...
>
>I have a strange problem with PIP-02 on my 386-40. Sometimes (in Windows) it
>won't work. I can tell when it will not because it when it signals (an
>audible chirp) it has executed a command, it does so quickly, and executes
>the command quickly, too. I re-load it and it usualy works fine. Listen for
>a slow chirp, around 1 second, to signal proper operation.
>
>
I believe the problem is that windows changes the values the the 8254 timer
chip randomly to suit itself. Sometimes the timer  value is very small and
this is why the beep is short and the programmer timings  short also. These
"serial only PC direct" programmers as I call them (when I'm being kind
rather than realistic), rely  on the timer chip as a constant timing
reference across different speed PCs. Well the better ones do but I have
seen some that don't even do this much!  (Seriously!).

There appears to be no way to easily accurately generate timing in windows
because, due to an IBM cock-up, the timer chip cannot be read by software,
if it could, great, no problem.

If you disable the interupts, that mostly stops windows from interfering but
the PC is running in virtual mode and will not allow  you to write your own
values to the timer.  I/O is privileged and writes to the timer disabled by
the controlling software. (suposedly you can stop this by editing the
"windows.ini" file but it didn't seem to work when I tried)

So, as there is no way to know whats in the timer or to put known values
there, your timing reference is gone.

I have spent many hours trying to overcome this problem. If anyone can tell
me if I'm wrong in fact or can suggest a way around this problem I'm
listening.

Of course, I realise there is the RTC and I haven't yet looked into this as
there are other considerations like old XTs with no RTC. Sur they can be
running windows either but you need to be able to tell what your dealing
with and there are many problems to deal with here.

So, put simply, don't run any of these, um, serial only PC direct
programmers in windows. Even if they appear to work, chances are the timings
are all wrong. Well, in some cases, they were wrong to begin with anyway.

Are you sure the documentation doesn't say something about windows
compatibility?

Regards,

Jim Robertson






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