[sane-devel] Parallel port ASIC problem?

John Coppens john@jcoppens.com
Mon, 6 Oct 2003 13:32:54 -0300

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,