Date: Mon, 18 Dec 2006 10:10:58 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: mrcomputerwiz@hotmail.com Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Capturing Parallel Port Data Message-ID: <20061218.101058.1102528461.imp@bsdimp.com> In-Reply-To: <BAY127-F2600E499F0FAE61D967201B3D40@phx.gbl> References: <200612152025.17442.doconnor@gsoft.com.au> <BAY127-F2600E499F0FAE61D967201B3D40@phx.gbl>
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In message: <BAY127-F2600E499F0FAE61D967201B3D40@phx.gbl>
"Mr CW" <mrcomputerwiz@hotmail.com> writes:
: Thank you for the pointers. It sounds like reading data back from the
: parallel port is not a common thing to do, although I thought parallel port
: projects might have done this. Then I realized that most PIC programmers,
: parallel port displays, etc. usually only receive data, not send it back to
: the computer...
:
: I'm still looking into this, so any other suggestions are very welcome.
I've used parallel port connections in a few different products.
Usually, it is boring DIO stuff. Not worth mentioning here, and we
use ppi. However, sometimes we need data. For that we write a
driver. We connect the ACK line up as a 'data valid' line and then
read the data and/or control pins when it strobes inside the ISR. We
use another line to 'ack' the data (which is backwards from how a
printer works).
Warner
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