RE: [PARPORT] Realtime control of parallel port

Darren Bilby (
Tue, 28 Dec 1999 10:38:19 +1300

Just been doing some of this myself. The parport code was excellent but had
a pretty high overhead for our equipment and it was hard to debug when our
hardware was doing bad things.

In the end we found it easiest to bypass the parport code and just use iopl,
outb and inb. It does means you need a good understanding of the standard
you are using. If you don't need it fast its pretty easy you can get a doc
off the net, however, if your doing ECP or EPP I would recommend getting the
IEEE standard.

If you want realtime you will need to go to realtime linux (rtlinux), it
looks formiddable at first but its pretty simple to get going. We have our
equipment running under rtlinux, and its incredibly stable and accurate,
pumping out around 1.5Mb/s in non-DMA mode on a standard ECP port. We have
also added DMA support by using the parport code as an example.



-----Original Message-----
[]On Behalf Of Robert Norgard
Sent: Tuesday, 28 December 1999 9:24 am
To: Linux Parallel_Port
Subject: [PARPORT] Realtime control of parallel port


Could someone point me in the right direction for
direct, realtime, bit manipulation of the i/o lines on
the parallel port, please.

I need to take direct control of the port for control
of external equipment. Any suggestions also


Bob Norgard,
Anchorage, AK

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This archive was generated by hypermail 2.0b3 on Mon 27 Dec 1999 - 16:43:08 EST