William's Homemade Computer

[yuhong]

http://dubel.org/computer/

A rig like this would be useful for reading the EDX on reset, particularly on older CPUs that do not have CPUID.

 

[glitch]

Wow, all that work for one credit?! Were you required to use a CPU as complex as a 486?

 

[barythrin]

That's really interesting. I'm surprised it looks so simple in theory.

 

[sergey]

Nice system. Not very useful though beyond completion the course requirements.
I am also a bit surprised by CPU selection. Z80 would be a better fit
But if you take x86 compatible CPUs, I think that interfacing to an i486 (or i386) is easier than to an 8088 or 80286 (no need for bus controller, data/address bus demultiplexing, clock generator, etc). The only problem that you need to have 32-bit memory (and so more SRAM/EPROM chips and more wires).

 

[Chuck(G)]

If you want easy, a 80188 or V40 doesn't get much simpler.

 

[yuhong]

Nice system. Not very useful though beyond completion the course requirements.
I am also a bit surprised by CPU selection. Z80 would be a better fit
But if you take x86 compatible CPUs, I think that interfacing to an i486 (or i386) is easier than to an 8088 or 80286 (no need for bus controller, data/address bus demultiplexing, clock generator, etc). The only problem that you need to have 32-bit memory (and so more SRAM/EPROM chips and more wires).

I think there is also the 386SX, as well as BS16 and BS8 signals.

 

[Chuck(G)]

The AT&T PC6300/Olivetti M24 had an interesting take on this. They mounted the battery on the motherboard all right--but the motherboard in those machines is mounted component side down. So the leakage (yes, it happens there also) drips down on the bottom cover and not up onto the PCB.

 

[yuhong]

The AT&T PC6300/Olivetti M24 had an interesting take on this. They mounted the battery on the motherboard all right--but the motherboard in those machines is mounted component side down. So the leakage (yes, it happens there also) drips down on the bottom cover and not up onto the PCB.

Wrong thread?

 

[Chuck(G)]

Yup--it belongs under the "leaking battery" thread. That'll teach me to have two threads open at the same time.