Hello,
I try to use dual monitor system in my Pascal (Free Pascal exactly) programs.
I'm able to use the system, where there is VGA card as primary and the Hercules as secondary graphic card (it starts in text mode, so I can write to the $b000 immediately and it works without any assembler initialization). When there are AGP as a primary and PCI as a secondary, I use the COM driver from www.asm32.com, which programm the North Bridge so the PCI card became the MDA, so I can work with it as in the first case.
Now I try to combination of primary PCI SVGA graphic card (Cirrus) and as a secondary I use ISA VGA card Trident 9000B (when I use 9000C, it didn't work at all, when I use the UMC, the primary card started as MDA because UMC became CGA, which I don't want to).
The primary card starts in normal mode, so I can use it in full way. It is also primary initialized. The second card (ISA) is represented by MDA adapter (when I use MSD in DOS, there is a second adapter as MDA, when I read the MDA ports, there is MDA setted up correctly (on system, when there isn't the second adapter, these ports are always $ff) in $3b8).
But at the monitor there isn't nothing. It looks like the adapter doesn't provide an output. I tested the monitor it works, also the adapter when it is alone, works too. Also in $3ba port there isn't activity on bit Horizontal Drive (which is on VGA and Hercules system). I tried to do something with switches on the card, but all documentation I have there are always three pined switches and my card has only two pins in every switch. Otherwise, no matter what I set, the card works always the same way. The EGA 2 ports $2Cx are deaf ($ff), only some CGA registers sometimes changes, but it's done also on single adapter system.
Does anybody know what I should do about this to manage it works?
Thank you very much in advance.
Martin Lux