pyserial problem

Wouter van Ooijen wouter at voti.nl
Wed Aug 7 21:21:31 CEST 2002


I use pyserial 1.17 on a win2k PC to communicate with a device (PIC
microcontroller) using a serial port. This works OK most of the time,
but sometimes I get strange effects. This seems to happen much more
often when the PC is busy (for instance retrieving email).

There are two problems that can occur with the sending of data (data
is always one character):
1 the write call returns, but the character is not sent (my software
waits for a response which will of course never come). When I send the
next char the original char *is* sent (and the next char is sent
also).
2 the write call simply does not return.

I changed the serialwin32.py code to use non-overlapped IO, but effect
is still the same: works most of the time, but fails sometimes,
especially when the PC is busy.

someone got a clue?


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting



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