Michele Debandi wrote:
>
> Hello,
> having a standard isa serial board (with two National 16550 or
> equivalent), is possible, under Linux make both prot sharing a single
> interrupt, eventually modifying the serial board.
Yes, it is possible, I have in my home PC four std serial ports, where
ttyS2 & ttyS3 are both on IRQ9.
> As far I can remember INTR on ISA BUS is a standard TTL signal active
> HIGH, so I could simply add two diodes or an AND logic gate to make the
> hardware happy (I'm not to sure about this, but at a quick read of
> UART's datasheet, seems ok to me).
There is cca 1kOhm from IRQ line to +5V somewhere on my MB (Gigabyte
TX3). This is the main problem with "diode logic", IRQ line must be
forced low with ~100 Ohm to GND and the current from IRQ drivers becomes
slightly high. One AND gate will be probably better.
> Then having a PCI machine, the interrupt logic on PCI bridge have to be
> set up to level triggered instead of edge triggered.
>
> Anyone have experience on these things, or have some sample configuration
> for linux?
>
> Any help is appreciated
>
> 73 de Mike iw1cfl
73! Tom
