M8207 anyone?

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Wed Aug 9 23:33:50 2000

At 09:27 PM 8/9/00 -0400, Allison wrote:
>Read up on parallel ports for PC first, the M8027 WILL NOT be sufficient.
>Most parallel ports ahve enough bidirectional lines and the 8bit data is
>bidirectional (only the old XT ports aren't).

I have, and they are, _if_ they are CENTRONICs compatible. There are 11
output bits and 6 input bits. When you have such a port on your PC (and
even PC/AT and some 386 machines had them) you could use them in "nybble"
mode. In this mode four of the 8 data bits are outputs, Busy/SLCT/Paper
Out/Fault are inputs, strobe is "write nybble", ACK is "read nybble", and
the upper four bits are used to control things like interface direction and
turn around. In this way a general 4 bit bi-directional interface is
created that can run and 400KBits/sec on some machines! (typically closer
to 300Kbits but still)

Ports that aren't Centronics compatible _really_ don't always work. However
I could also try it with a M7941.

--Chuck
Received on Wed Aug 09 2000 - 23:33:50 BST