[sane-devel] Parallel port ASIC problem?

stef svoltz@wanadoo.fr
Mon, 6 Oct 2003 21:15:20 +0000

On Mon, Oct 06, 2003 at 01:32:54PM -0300, John Coppens wrote:
> Hello people.
> This is not strictly a scanner problem, but I believe scanner hardware is
> relatively similar to the webcams - at least the bus interface.
> I'm playing with a parallel port webcam (weeCam), and hope to get it
> working for an experiment with a microprocessor (at the university).
> Once in a while, the communication completely hangs - even libieee1284
> cannot seem to get out of it. Only solution is to abort the program,
> remove ppdev and lp, and power cycle the camera.
> I suspect the ASIC in the camera get into a weird state and some special
> code sequence is necessary to get it out of it.
> Has anyone had a similar experience? I'm guessing that such states can
> appear with most ASICs, and (guessing again) that it might take a special
> combination of the control lines to get it out of that state.
> Thanks in advance,
> John


	such reset sequence vary a lot from ASIC to ASIC. For instance, the 
UMAX 1220P scanner uses an EPAT C7 based ASIC, however, none of the reset
sequences found in parport-scsi for EPAT worked.
	But who knows ? Maybe it could work.