Re: [PARPORT] Buffer read/write verification

Tim Waugh (
Sat, 20 Mar 1999 15:26:12 +0000 (GMT)

On Sat, 20 Mar 1999, Dale Whitfield wrote:

> I still disagree, I'm afraid Tim :-)

You are free to do so.

> Because it won't work. Simple.

So, to get this straight, your device talks ECP mode on the wire, but
using the IEEE1284 features of the hardware to talk ECP with it won't
work? Have I understood you?

> For those unsure of what this means, the issue is simply that it is
> possible using ecp-mode to send/receive an address/data byte in
> hardware mode (hardware handshakes control lines) or software mode
> (handshaking of control lines done in software).

You haven't shown me a datasheet that says it is possible to read an
address byte in ECP mode by getting the hardware to do the handshaking.
You said WinBond -- I looked up the datasheet and it said no such thing,
as far as I could tell. Yes, you can read from ecpAFifo, but there's no
guarantee of its contents (it explicitly says that later on). That's just
another way of saying that it's write-only.

> The QuickCam VC using both hardware and software modes in differing
> circumstances.

Dale, how does the QuickCam know if software or hardware is driving the
timing of the signals on the wire?


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This archive was generated by hypermail 2.0b3 on Sun 28 Mar 1999 - 17:04:25 EST