Date: Tue, 3 Aug 2004 13:04:55 -0300 (ART) From: Fernando Gleiser <fgleiser@cactus.fi.uba.ar> To: hackers@freebsd.org Subject: Controlling external hardware via lpt0 Message-ID: <20040803125019.O1361@cactus.fi.uba.ar>
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First, I apologize if this isn't the right place for asking this things I need to control some external hardware with a small program in FreeBSD. I thought about using the 8 data bits of the parallel port for sending the control bits to the hardware. The hardware is a very simple combinational logic, triggered by level, I don't need any flow control or such. The soft opens /dev/lpt0 and then writes whatever value is needed (i.e, if I need the 2 lsb to be high and the rest low, I write 0x3) The problem is, I can't even open the paralel port for writing, it always fails with EBUSY. on the parallel port I attached a DB-25 wired as a "dummy printer", that is: strobe->/ack, busy, paper end and select inh, wired together and then sent to pin 18 (GND). Is there anything I'm missing? Are there a "programming and using the parallel port in FreeBSD" guide? Thanks in advance Fer
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