The TI 34010

From: Eric Smith <eric_at_brouhaha.com>
Date: Fri Mar 5 22:18:52 1999

Derek wrote:
> Exactly why isn't it VGA-compatible?

The 34010 isn't even *similar* to a VGA. The exact extent of the
compatability is that both hook up to a host processor, and both produce
a video output.

> I thought that certain things are true of the 34010:
> - flexible memory architecture

If a large flat address space is a "flexible memory architecture",
then the 34010 certainly has it. However, that isn't what VGA uses. VGA
has all sorts of crufty bank switching and other disgusting hacks.

> - many operations done in software (not hardware)

Actually most of the interesting operations of the 34010 are done in
microcode. But those operations aren't similar to VGA.

> - some hardware (video RAM, shift registers and other parts to
> actually produce a monitor signal) external to the 34010

Yes.

> It's certainly possible to emulate the Hercules, CGA, and MDA. Is there
> some lack of configuration registers, or some internal timing constraint,
> that makes emuilating the VGA impossible?

The 34010 doesn't have any built-in support for emulating any of those things.
Sure, you could do it by adding a big pile of external logic (which you could
put into an ASIC, or some PLDs). Due to communication overhead, it would
be a fair bit slower to emulate a VGA with a 34010.

It's cheaper and easier to just put a VGA controller on the card, since that
does exactly what you need in a single inexpensive chip. Leave the 34010
to doing what it does well. For example, acting as a display list processor
for AutoCAD. The VGA interface is too low-level and baroque to be
efficiently emulated in software.

Eric
Received on Fri Mar 05 1999 - 22:18:52 GMT