Using serial devices under SCO Xenix above COM 2

[Ivar Hosteng]

barton at holston.UUCP (barton) writes:

>Recently the excerpt below was posted by Ross Oliver at SCO.

>>However, if you can set these boards to use other interrupts, then you
>>can use them alongside existing COM1 and COM2 devices.  To do this, you
>>will have to modify the /usr/sys/conf/master file to tell the serial
>>driver to handle the additional interrupts.  Modify the "vec3" and "vec4"
>>columns for the "sio" entry, then rebuild your kernel.

>>Ross Oliver
>>Technical Support
>>The Santa Cruz Operation, Inc.


>My question is:
>How do the entries in the vec3 and vec4 
>columns relate to the COM ports and what values should
>be placed where? Since vec1 and vec2 are 3 and 4 respectively,
>am I correct in assuming that vec1 is for COM2 which is
>normally IRQ 3 and that vec2 is for COM1 which is normally
>IRQ 4 ??

>If this is true, then are the vec3 and 4 columns also reversed
>i.e. COM4 and COM3 respectively?

>I recently tried this with an internal modem that supports
>COM1 thru COM4 and IRQ2 thru IRQ5 to no avail.

>Does anyone have any suggestions or better, definate answers?

I have a way to get one of your extra com ports working. The reason why you 
can't use both is that IRQ2 is usless for communications. To make the com port
at IRQ5 work you have to make the following changes to the file
/usr/sys/io/sioconf.c. Include the following line:

{2,IBM_BOARD,  1,5,1,  (sd)0x3e8,0,                 0,MCRBIT3}, /*ibm COM3*/
                           ^^^^^
		change this to the base address of your COM3 port.

Change this line in the master file:

sio      2  0577 104    sio  0   0   5    1   7    3     4     0   0   

to this

sio      3  0577 104    sio  0   0   5    1   7    3     4     5   0   


That's it! Just make the new kernel ( cd /usr/sys/conf and type make) and 
reboot your system. If all goes well you should see the new port in the 
startup display. Then enter single user mode and type:

mknod /dev/tty1b c 5 1
mknod /dev/tty1B c 5 129

Good luck!
-- 
Ivar E. Hosteng,	Advanced Computer Consultans, Oslo, Norway
Internet:		ivar at acc.uu.no
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'Just what do you think you are doing Dave?'	-HAL9000