[OpenBIOS] VGA card and screen output
Wallace I. Kroeker
WallaceKroeker at smarttech.com
Mon Feb 7 11:44:00 CET 2000
Hello,
I FINALLY managed to get the screen output working. (A side benefit is that
I now know a lot more about the 440BX chipset as I assumed this was not
being initialized properly)
The card that I have in my system is an ATI Rage III PCI.
I finally added some code in START.ASM to initialize the VGA BIOS (from the
reading I've done the VGA cards have their own Video BIOS). This required
the following:
* Initialization into 07h mode (monochrome 80 x 25 ... MDA mode)
* Loading of a Character set (the cards come with a few predefined)
* Activate the Character set that was loaded
* Now the VGA base has to be 0xB0000 (MDA location actually) in
Firmware/init/vga.h OR configure the video to be MDA
The actual initialization was done using INT 10h in start.asm. If anyone
has suggestions on other ways to do this let me know.
I am currently working on getting the floppy enabled.
(The idea being to have a minimum BIOS that can actually be put into the
BIOS flash but still allow boot from disk for debugging or re-flashing)
Has anyone already started this?
Glad to hear Ron managed to get around his NVRAM write issue.
Wallace
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