24 Nov
2009
24 Nov
'09
1:23 p.m.
On Tue, Nov 24, 2009 at 06:59:28AM -0800, Rick Bensene wrote:
I seem to rememebr it's easier to do this on a PCjr than on a PC (ISA
bus). The reason is that the PCjr doesn't have a DMA controller, but had
the signals brought out to the expansion connector to allow one to be
added. And those signals, of course, include the bus request and grant
lines so the DMA cotnroller can take over the bus from the CPU. Which is
exactly what you need to add a hardware frontpanel (at least to access
memory and I/O devices).
I think most 16 bit ISA ssytems have a signal on the bus slots which lets
you do that, but I will have to check the 5170 techref...
-tony
OK, so this might break the ten year rule, but
I'm curious.
Has anyone ever built a switches and lights front panel for a PC?
Sort of:
http://www.vintage-computer.com/vcforum/showthread.php?t=17451
It is a PCjr and it looks really neat, there is a link to a youtube clip
there as well.