• Please review our updated Terms and Rules here

Express Card 286 & an NEC V20 CPU?

I'm just poking in the dark here. Does the Express Card have a ROM on it? Perhaps you can dump it, edit it to look for the ID of the V20 instead of the 8088 and reflash it?
 
I seem to remember CPUs older than the Pentium or something didn't even have any kind of CPU ID... Are you sure that's the case?
 
A program can determine whether its running on an 8088 or V20 by tests instructions that work on the V20 but do not exist on the 8088. The 286 Express is entirely controlled by software, however the OP seems to state that his system will not boot at all if the 286 Express is installed with a V20. If that is the case, there must be a fundamental hardware incompatibility between the 286 Express and the V20, which would only be solved by redesigning the board.
 
That's very odd. There are some very timing-critical devices on a standard PC motherboard that the V20 works very well witih--such as the DMA controller, the system bus controller, etc.

So we have the whole picture here? It's a little difficult to understand exactly what you're doing with so little information.
 
So it fails to work when the V20 is installed, but works fine if you put an 8088 back in it?

My guess would be that the program to enable the 286 does a check first to see if it is already running on the 286 by testing for the presence or lack of some specific CPU instruction or feature. And most likely the program doesn't know anything about V20s. So when it runs on the V20 it thinks the 286 already is running, and stops.

Can you post or link to exactly what software you are using?

If you have a 286 accelerator, why do you need the V20?
 
SomeGuy said:
So it fails to work when the V20 is installed, but works fine if you put an 8088 back in it?

My guess would be that the program to enable the 286 does a check first to see if it is already running on the 286 by testing for the presence or lack of some specific CPU instruction or feature. And most likely the program doesn't know anything about V20s. So when it runs on the V20 it thinks the 286 already is running, and stops.

Can you post or link to exactly what software you are using?

If you have a 286 accelerator, why do you need the V20?
Click to expand...

No software at this point..... The 1000 gives a continuos BEEP and won't even POST.

V20 is about 20% faster so nicer to fall back to a V20 tan an 8088.

I suspect the same as yourself, the card firmware thinks its already in 286 mode and crashes.......
 
I have the V20-10 in my 1000SX. I never had a Tandy Express Card (25-1035) and would mind acquiring one if the price was right, but that's another story. It would be nice to see some benchmarks between two similarly configured 1000SX's - one with the V20 and the other with the 286 Express.
 
You must log in or register to reply here.
Back
Top