🚀 go-pugleaf

In order to read-in through a PC's parallel port, you need to either:

	(1) Disable (ie, tristate) the output driver. If your card
	uses an ASIC, it might be difficult. I think the 16452 from
	VLSI Technology has an output-enable function.

	If there is a genuine 74xx374, you can put a switch on the OE
	pin. I would be very cautious about using an unused bit on the
	control port to drive OE because some wacko software [about 99%
	of what's out there :-{ ] might disable your port.

	(2) Or, 'backdrive' the output driver. Try writing 'FF' to the data
	port (278h, 378h, or 3BCh) and use a beefy driver to yank-down
	the lines. Be careful, because there are several types of RC filter
	topologies for slew-rate/spike protection; if the readback buffer
	is *between* the resistor and the port connector pin, you might
	have some trouble.

----- Boycott redwood products ---------------------------- Recycle -----
                                                                 #####
{uunet!tektronix!gold!grege}     Register to vote, then        ##  |  ##
grege@gold.gvg.tek.com           vote responsibly             #    |    #
							      #   /|\   #
Support high oil prices, waste tax $$ on war, evade domestic   #/  |  \#
problems, and die young on foreign soil- Just say YES to Bush   #######