Message-ID: <56@unc.UUCP>
Date: Tue, 15-Jan-85 14:59:35 EST
Article-I.D.: unc.56
Posted: Tue Jan 15 14:59:35 1985
Date-Received: Fri, 18-Jan-85 01:51:12 EST
Organization: CS Dept., U. of N. Carolina at Chapel Hill
Lines: 22

I have written an interrupt driven communications program that works fine
on the XT but fails under certain conditions on the AT.  These conditions are:

1.  High volume of transmission & received data at high baud rates
    (4800 or 9600 baud)

2.  Any kind of receiver error (such as a parity error).

I use all four possible communications interrupts (receive data available,
transmit buffer empty, line status, and modem status).  I have tested a few
other programs that are similar to mine and they all failed on the AT except
one that used only the receive data interrupt.  One that failed is a program
from IBM!

I tried putting delays after every I/O port access; but the longer I made the delays, the more pronounced the problem became!  The symptom is an apparent
shutdown of the RS232 interrupt system.  After the screwup, I never get a 
communications interrupt again.

I am at the end of my rope.  Can anyone give me a clue?

Thanks
Edmund Burnette