-> All you need is an old PC/XT or 286. You raise a chosen output, write the data
-> byte and wait for an ACK, then repeat waiting for loss of ACK.
Yes, but the PC/XT or 286 would have to be equiped with a bidirectional
parallel port, unless you want to use a 4 bit protocol over the control lines
(like what laplink used in the old days) with a special cable.
Another thought: if you do use an old PC, why not connect it's serial port to
a serial port on the Linux machine and use the serial console driver. The PC
could write all information passed on the serial port to a file with a
(configurable) maximum size. This minimizes the programming effort (a simple
program on the P.C. is enough) and requires no special hardware.
On the other hand, not everybody has an old machine lying around so what I
would like to do most is design a protocol (parallel or serial or even both)
that allows people to use either an old machine or a cheap dedicated DIY piece
of hardware.
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Hugo Van den Berg - hbe@cypres.nl
Phone - +31 (0)30 - 60 25 400
Fax - +31 (0)30 - 60 50 799
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