dav@genisco.uucp (David L. Markowitz) (10/21/89)
I am in the process of writing a driver for a Univision 1024 frame buffer, and I have a few questions. First the details. I have ten years of Unix experience, and have written many drivers, but I've never worked with Xenix or DOS much. My background is Vax/68000/Sparc and VME based, not Intel and AT bus based. The hardware: Standard stuff: SCO Xenix 2.3.2 Micronix 20MHz 386 + Cache 2 MB RAM 80 MB Hard Disk Monochrome Video Board I am adding: Univision 1024x1024 frame buffer with VSB bus Tecon DVX1024 Frame Grabber with VSB bus I already have the Tecon mostly working (it won't interrupt, though). I need to map in 64K chunks of the video memory on the AT bus. The board includes registers to set up which piece of video RAM is mapped to the bus, but I don't know how to interpret Intel-style addresses like C400:0200 within a driver. I do not need to use this as my console device, nor does it need to interface to the standard video boards data structures (although that would be nice). I really just want to use it as an alternate stand-alone display, while also having the monochrome display hooked up. Now, the questions: 1) Has anyone already written this? How about other memory mapped video board drivers? Are there any floating around in source form that people wouldn't mind letting me look at? 2) How do I access the bus at such an address from Xenix? 3) Is there a good manual/book somewhere on how Xenix deals with the fractured concepts of the AT bus. (Or, "Gee - a real computer! Too bad it can't talk to the rest of the world very well...") (When Sun designed their 386i machines, they had to figure out how to co-exist with the AT bus. Their solution? "We don't use it!") 4) Am I crazy? Please reply by mail - I will summarize if there is enough interest. David L. Markowitz Genisco Technology Corporation dav@genisco -- David L. Markowitz Genisco Technology Corporation dav@genisco