ISA video card w/ a microcontroller.

- C
- Charles Douvier
  
  Contact options for registered users
posted
20 years ago

Sat, Aug 16, 2003 4:20 PM

Hello,

I spent 8 hours on goole yesterday and 4 hours on google groups .. so I am pretty sure this answer isn't as quick as a look @ this link.

I am trying to use an ISA VGA card for a text console for a microcontroller. I want to use the 80x25 mode (I think they startup in this mode automatically). Does anyone have some extended information on how to do this? From what I have read I can just write the ASCII character to the 8 bit data port and strobe, but I don't know anything about the following bit to be sent (color/inverse video bit) or any display movement commands, etc.

Thank you, Charles

- A
- Arie de Muynck
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sat, Aug 16, 2003 4:37 PM

Quite likely the VGA card has it's own BIOS that has to run before the card behaves like a proper VGA card. That BIOS ROM hold 80x86 instructions...

If you want to program the chip set directly, look for

Ferraro, R.F. - Programmer's guide to the EGA and VGA cards Addison-Wesley

It is old but describes most (older) ISA card chipsets and has driver sources for them.

Regards, Arie de Muynck

- B
- Brett
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sat, Aug 16, 2003 5:15 PM

card

Or emulate x86!

- A
- aurgathor
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sat, Aug 16, 2003 6:50 PM

W.r.t. 80x25 text mode, VGA is functionally equivalent to CGA and EGA in text mode, and there should be truckloads of reference on that. I'm not sure how to do that on a non-PC compatible embedded system, but the easiest (?!) thing is probably writing directly into the display memory. If I can find it, some time ago I wrote a nifty test program to access video memory.

- A
- Alex Gibson
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sun, Aug 17, 2003 2:02 PM

see

formatting link

for video projects using avr's

- J
- Jim Granville
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Sun, Aug 17, 2003 10:43 PM

VGA cards have Boot-Roms, and part of the PC startup, includes a call into these, that set all the VGA chip registers. To run ISA cards, on a non X86 uC, ( if you can still buy them ) you need to reverse-engineer the BIOS Rom. It can be done, but it is 'non trivial' and non portable.

We can offer something close :) See

formatting link

This was designed to replace ISA-VGA cards in microcontroller systems. It runs in 80x25 VGA text mode, (640p x 400p), and has scalable text. Interface is serial-FIFO, so is uC friendly.

-jg

- H
- ""honeypot"
  
  Contact options for registered users
Vote on answer
posted
20 years ago

Mon, Nov 24, 2003 11:04 AM

VGA card does not initialize automatically, onboard bios has code for CPU to initialize it. You can hook the VGA card up to microcontroller and hardwire most of the address bus, but you still have to take care of 16-bit data bus, control signals, and initialization code. I've considered this approach quite a bit and found that it proabably wont work all that well...