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CD ROM Paradise Collection 4 1995 Nov.iso
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550reset.doc
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1994-10-19
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550RESET.DOC formatted Wed 10-19-1994 15:11:27
This program clears the 16550A's FIFO to prevent system hangs
when "Super I/O" cards with SMC665 or SMC666 chips are used
with communications programs that enable the 16550A UART. Just
run this program before you run your favorite communications
program and you should *not* experience further system hangs.
NOTE: If you have an external device connect it and turn it
on BEFORE you run this program.
The specific problem is that if you output a 0x7 to the FIFO
control register of these chips while there is data in the
FIFO the chip will go into a state where the Receive Ready
flag (bit 0 in the LSR) remains high NO MATTER HOW MANY TIMES
YOU READ THE RECEIVER BUFFER REGISTER. If your communication
program is unfortunate enough to enable interrupts while the
UART is in this condition your system will lockup, and require
a hardware reset or power cycle to restore operation.
Needless to say this is inconvenient!
I discovered this problem when I upgraded my "SUPER I/O card"
to a "SIDE jr L" vlb card. While the features are great I
immediately ran into problem with EVERY program I have that
uses serial I/O. I found that I could only execute Windows
programs that used serial I/O once, the whole system locked up
the second time I ran the program. This occurred with several
different Windows programs. Searching the Microsoft Knowledge
base yielded the answer... an updated SERIAL.386 driver
(search for WG1001 for the new driver). Unfortunately the new
Windows driver did nothing for DOS programs I use regularly
such as Qmodem and Telix, that is why I wrote this program.
The Microsoft writeup provided enough information on the
problem for this program to be written.
Comments are welcome:
Skip Hansen WB6YMH.
internet: wb6ymh@amsat.org
BBS: (310) 541-2503
Packet: WB6YMH@WB6YMH.#SOCAL.CA.USA
If you find this program of value I am pleased, send no cash!