Tim Waugh (email@example.com)
Tue, 15 Feb 2000 10:39:55 +0000 (GMT)
On Fri, 11 Feb 2000, Eugene Weiss wrote:
> Believe me, I'm aware of them and thought about that, but:
> 1. I was already in SPP mode (the ECR value was 0x5, hence mode 000)
> 2. I was trying to switch to mode 001
> 3. The bit that needs to be set is bit 4, the interrupt bit, and not one of
> the FIFO bits.
Odd. I've checked a couple of datasheets and I can't find anything like
When failing to switch to mode 001, what are the high bits of ECR? Can
you write a small test case for us to try just using inb/outb? I'd like
to see if this is model- or vendor-specific.
> > Are you aware of the rules for "Mode Switching" as documented in the
> > ECP specifications 1.06/ISA Interface standard 1.14 (July, 14 1993) by Microsoft?
> > If the mode is not 000 or 001 then it can only be switched to 000 or 001.
> > If in mode 000 or 001 the port may by switched to any other mode.
> > There are too special rules concerning FIFO status and transfer phase before you
> > can
> > switch some extended mode to 000 or 001.
Incidentally, I've never actually verified that the parport_pc code
complies with any of these rules, and I suspect that it doesn't. If
someone has some spare time they don't know what to do with...
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