Tim Waugh (
Wed, 9 Dec 1998 08:52:45 +0000 (GMT)

On Wed, 9 Dec 1998, Thomas Sailer wrote:

> Ok, you're right. My doc (1.14) says "Reverse channel addresses are seldom used
> and may not be supported in hardware". And I really don't understand
> the programmatic interface. ecpAFifo is said to be operational
> only in forward direction. What happens if the peripherial wants
> to do a reverse channel address? Does the hardware simply stall? Or
> do bad things happen?

I see what you mean. I haven't read all of the MS ECP implementation spec
yet (which document are you reading?), but I can't see any way of finding
out the reverse channel address.

Given that, perhaps it's just never used. Does anyone know anything to
the contrary?

(The parport interface should still be able to cope with it, and I think
the way of doing that is for read to return early.)


-- To unsubscribe, send mail to: --
-- with the single word "unsubscribe" in the body of the message. --

This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:18:52 EST