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Unread 02-01-2006, 22:52
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Joe Johnson Joe Johnson is offline
Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
Team Role: Engineer
 
Join Date: May 2001
Rookie Year: 1996
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Re: PC Parallel Port Circuit

Yes. Sort of. It is quite easy to bit bang the pins of the parallel port. The reason I say sort of is your desire to power something. It depends on how much power you are trying to pull. I think you can get away with small power needs but power hogs are another matter.

KitsRUs.com sells a PC Data Acquistion Kit (available here) that I have used with good success.

Even if you don't want to use the kit (and you probably don't have to), it has a manual that shows a BASIC program that demonstrates how to access the various data & control signals of the parallel port.

The code is a bit criptic but if you are clever and know a bit about HEX you can noodle through it.

Quote:
a typical code example - line numbers are for reference

1. PORT = &H378
2. PE = 32
3. OUT PORT, &H00
4. OUT PORT, &H02
5. OUT PORT, &H00
6. OUT PORT, &H01
7. BITS = 0
8. X = INP (PORT+1) AND PE
9. IF X = PE THEN BITS = 128
10. FOR I% = 6 TO 0 STEP -1
11. OUT BASE, &H03
12. OUT BASE, &H01
13. X = INP (PORT+1) AND PE
14. IF X = PE THEN BITS = BITS + (2 ^ I%)
15. NEXT I%
16. PRINT BITS
Another nice thing about the manual is that it gives all the secret handshakes to get things to works (address of the various registers, etc.)

Good luck.

Joe J.
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