Date: Thu, 9 Mar 2000 16:11:07 -0800 (PST) From: Steve Willoughby <steve@ichips.intel.com> To: freebsd-hardware@freebsd.org Subject: parallel port problem on FreeBSD ThinkPad -- help? Message-ID: <Pine.A41.3.96.1000309160147.45702L-100000@pdx484.pdx.intel.com>
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I have a device I designed and built, which is hooked up to a computer's
parallel port. The circuit works flawlessly on one kind of system (a
Toshiba laptop), but on another (an IBM ThinkPad 600E) the parallel port
refuses to go. FreeBSD 3.3 is running on both systems. On the ThinkPad,
it just says the device is busy. I assume it's not seeing a "ready"
status so won't let me open /dev/lpt0?
Below is the way I'm interfacing to the parallel port. Can someone more
familiar with these things see where I'm overlooking something here?
PARALLEL PORT DEVICE
!FAULT 15-----------+5V
SELECT 13-----------+5V
ERROR 12-----------GND
GROUND 18-25-----------GND
!ACK 10----,
BUSY 11----+------> one-shot circuit, which pulls BUSY and !ACK high
,--------> for 10mS when !STROBE goes low (enough time for
| the circuit to act on the transmitted data)
|
|
!STROBE 1--+--------|>------->
D7 9-----------|>------->
D6 8-----------|>------->
D5 7-----------|>------->
D4 6-----------|>-------> (rest of circuit)
D3 5-----------|>------->
D1 3-----------|>------->
D0 2-----------|>------->
cmos
buffers
Thanks in advance,
Steve Willoughy
(Not asking or speaking for Intel, this is just a hobby thing...)
____________Steve Willoughby, Intel PMD Engineering Computing_________________
Stallman: "God told me I programmed the best text editor in the world!"
Torvalds: "God told *me* I programmed the best operating system in the world!"
Knuth: "Wait, wait -- I never said that." -- Erik Meltzer
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