Hi Michael,
there is a simple possibility to detect serial ports:
BIOS writes the addresses to memory from address 0040:0000, where is
0040:0000 com1
0040:0002 com2
0040:0004 com3
0040:0006 com4
0040:0008 lpt1
0040:000a lpt2
0040:000c lpt3
0040:000e lpt4
An entry 0000 means "not installed".
Detecting the proper interrupt may not be as easy but by default is
com1 irq4
com2 irq3
com3 irq4
com4 irq3
lpt1 irq7
lpt2 irq5
lpt3,4 ??? (means I don't know but who has 3 or 4 lpt in his machine :-))
An other interesting address is 0040:0010. It's the so called equipment
flag. It's a double word entry where the single bits mean:
bit 0 floppy available for boot
bit 1 numeric coprocessor available
bit 3,2 reserved
bit 5,4 initialised videomode: 00 EGA, VGA
01 40*25 mono
02 80*25 color
03 80*25 mono
bit 7,6 number of floppies-1 (00 means 1 FDD)
bit 8 not used
bit 11-9 number of com ports
bit 12 reserved
bit 13 internal modem
bit15,14 number of lpt ports
Addresses 0040:0000 to 0040:0010 are set by power on self test performed
from BIOS before booting OS.
Perhaps this will help You a little bit. And DON'T GIVE UP!!!
Regards Joerg
On Sun, 16 Jul 2000 02:48:56 +0100, Michael Polak wrote:
> Can someone confirm these deafult IRQ values for COM 1- COM3 ?
> COM1 Irq 4 base ?
> COM2 Irq 3 base ?
> COM3 Irq 4 base 0x3e8 ?
> COM4 Irq 5 base 0x3f8 ?? maybe I should look to my BIOS, but there
> must be Arachne users who know more about this than me..
> (You know, I was never really into PC hardware - I have upgraded from
> 8-bit Sharp Mz-800 directly to C programming.. this is why I like
> Linux - I don't have to care on which IRQ my /dev/modem or /dev/mouse..)
> Is COM1 Irq 2 or Irq 4 ?
> I am going to add these two notes to setup screens:
> 1) Use rahter "Manualy configured serial device" to those people
> who have COM4 but don't have COM3
> 2) The same to all those Com3/Irq 10 or Com3/Irq5 and other people...
> --
> Michael Polak: [EMAIL PROTECTED]
> Arachne Labs: http://arachne.cz/
> My mobile phone - up to 160 characters: [EMAIL PROTECTED]
-- This mail was written by user of Arachne, the Ultimate Internet Client
-- Arachne V1.60;b1, NON-COMMERCIAL copy, http://arachne.cz/
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