"[EMAIL PROTECTED]" ha scritto:
> At 01:58 AM 12/30/99 +0100, you wrote:
> > > Only thing left is the UART. modem uses UART 16550A and Computer uses
> > > UART 16550APN
> >
> >There is no "software" difference from 16550A and 16550AFN. Are you sure about
> >'A' after 16650? I know 16650 chips wthout 'A' get serious trouble with their
> >FIFOS.
>
> Yes, I'm sure enough about that, but the rest is new to me. Somewhere, on
> one of the many communities I frequent, a fellow posted about UART
> incompatibilities between old modems and new boards and said he had a patch
> that would fix it. At the time I didn't think I'd need it (famous last
> words) and now, well, here I am searching for it!
> what else could explain? Something other than irq, mechanical (cables,
> connections etc) or drivers?
> It's frustrating!
As never as my poor english ... I apologize for it.
It does not matter what kind of chip are you using, interface - software on 16550
family is the same this mean you'll find chip's register where you think should be.
If your mother board come with on board chips surely they are:
1) activable or de-act. via Bios setup program
2) They will use IRQ 3 and IRQ 4 and will be mapped in com1 and com2 I/O space.
Using COM3 and/or COM 4 means share the olny 2 IRQ lines, a special IRQ handler
will be required in this case. COM1 & COM3 will share the same IRQ3 line and COM2
and COM4 will share IRQ4, interrupt handler must detect the irq from chip checking
UARTS#1 and UARTS#2 like as polling system.
Your troubles should be made by :
1)Modem I/O register will map on the same I/O on board chips' space. (COM1 & COM2)
2)You already have 4 com ports. I don't this one is your case ";^)
Run MSD.EXE and check if your COMs can be detect as COM1 and COM2 without plug your
modem card then insert this one and re-start MSD: You should see 3 COM ports, if it
is not you get surely trouble #1. In this case try to disable your COMx (x=1,2)
from BIOS and restart MSD.EXE until you'll find 2 COMs.
If you have modem card manual send a "scan" to me I'll give you more information
about config its jumper to work correctly.
>
>
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