Third serial port
Steven H. Izen
izen at amelia.nas.nasa.gov
Fri Dec 22 16:52:58 AEST 1989
In article <%??HY=@b-tech.uucp> zeeff at b-tech.ann-arbor.mi.us (Jon Zeeff) writes:
>>I am having trouble installing a third serial port in my 386 running
>>ISC Unix/386. I have the X5 update (new serial driver). I have the
>>card set to IO address 3E8 (COM3), IRQ 2, and I have added appropriate
>>lines to /etc/conf/sdevice.d/asy and remade the kernel.
>>Unfortunately, I don't seem to be getting any interrupts from that
>>device. All output seems to be at about one character per second,
>>Does anybody know if it is possible to use IRQ 2 for a serial port?
>The AT bus generally has many unused interrupt lines. All you have to do is
>run a jumper wire from your serial card to something that has a 16 bit
>connector. Try INT 10 or 15 (you need an AT tech ref manual to show you
>what pin).
Whoa. I tried that with my second serial port under 386/ix. I changed
*everything* that needed to be changed to point to the new interrupt
including some stuff in the appropriate header files. It didn't work! The
kernel built o.k. and I saw characters going out to the modem, but incoming
characters were lost, and a message which was something like "stray channel
interrupt" (I forget the exact message) was sent to the console. Nothing I
tried would work with the 386/ix asy driver. Admittedly this was 2.0.1, before
i installed the x5 update and 2.0.2.
My solution: I freed up an an interrupt by doing the interrupt remapping trick
suggested above to my second parallel port. All that I needed to do was put
the appropriate irq # into the device file and rebuild the kernel. It works
quite well. The lp device driver on 386/ix is robust and seems to work quite
well! (as opposed to the infamous asy drivers). I know the author of the lp
drivers reads the net, and he is to be congratulated for a job well done.
(sorry, I forgot your name, otherwise I'd mention it.)
--
Steve Izen: {sun,uunet}!cwjcc!skybridge!izen386!steve / Quote corner:
or steve%izen386.uucp at skybridge.scl.cwru.edu /
or izen at cwru.cwru.edu /-------------------------/ My second bike is a car.
| The problem is that I *was* paying attention.
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