POST Probes -> Was -> Re: Here's a plan

[Matthew Sullivan]

Hi

James Oakley wrote:

> Matthew Sullivan wrote:
>
> > MicroPose (MicroProse?) - do the Micro2000, which is a rather useful
> > POST probe.....
> >
> > It's not cheap, but well worth it for the usefulness, it is listening
> > address configurable, and will provide extra diagnostics like Osc check,
> > clock check tri state logic probe, and of course all the voltages....
>
> We *could* make our own. A POST card is an ultra-simple device, It
> simply latches data from a specific port reserved for POST (I forget
> which one off-hand though) and displays it via either a bank of 8 LEDs
> in binary or two 7-segment LED displays in hex.
>
> There are schematics in many electronic magazines (when Microcomputer
> Journal was Computercraft, I believe they ran one, I think Popular
> Electronics also ran one a while ago). I can search through all of my
> old magazines to find the basic schematic.
>

Practical Electronics - about 3-4 years ago did one as well.....

The Microprose one is rather good, and my recomendation because of the book
that comes with it, it's _very_ comprehensive on what you should expect to see
from each BIOS, which whilst we are writing our own, it will remind us what we
should be pushing to the port on boot, and of course what we should testing on
boot...

> We can add extra features as we wish, for example, a PIC could be thrown
> on there to translate the data to a serial port (on the card, of course)
> or to an LCD module with extra information. It doesn't matter that the
> PIC is slower than the PC.
>
> We could also add extra functionality such as a simple parallel i/o
> port, i2c (which the PIC could handle nicely), analog switches, etc. We
> could set it up to display POST codes on an LCD or LED module on the
> front of the PC (it gets hard to read the display on a POST card if
> other cards are blocking it).
>
> We could even build a ROM programmer into it as an external module.
>
> This is an easy design, even with all the extra features. I have an ISA
> prototype card I can play with.
>
> The most expensive part would be, of course, the PCB (I paid CAN$50 for
> my prototype card) but if a bunch  of us wanted to make some (I have
> many friends who would be interested in such a device, parallel ports
> tend to run out quickly) we could get away with some relatively cheap
> PCBs if we find the right place (I hear ExpressPCB is pretty cheap).

I would say that we would probably only want a 'diagnostic/dev' card rather
than one with lots of extras...

However a useful feature might be a dual BIOS socket with a switch circuit of
some sort (digital electronics design is not a strong point for me) just to
save yanking the 'good' BIOS for replacement with the 'corrupt' BIOS to
re-programme it.

>
> If anyone's interested (we *will* need post cards, especially for
> debugging purposes), respond. It would also be nice to have a ROM burner
> on it as I'm sure we will all need one of those as well.


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