Re: USB printer cable for data I/O
- From: Iwo Mergler <Iwo.Mergler@xxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 04 May 2006 10:36:25 +0100
matteo.brusa@xxxxxxxxx wrote:
Hi,
i'd like to use a USB printer cable to control some switches for home
automation.
How can i control the value of every data line of the parallel
interface?
Since i'm not on a PC architecture, direct output to the port is not
possible.
Any idea?
MatB
You cannot rely on controlling the pins in the same way as
you can with a standard parallel port.
However, the simplest parallel printers simply use a strobe
signal to latch the 8 data bits internally.
You can duplicate that circuit with a 74LS374 octal d-flipflop
IC. You tie the /strobe line to the clock input.
If the printer driver expects to be interrupt driven, you may
have to also generate an Ack signal to make it work.
You then just send a byte to the printer which is held on the
output lines of the 74LS374 until you send the next one.
Regards,
Iwo
.
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- USB printer cable for data I/O
- From: matteo . brusa
- USB printer cable for data I/O
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