paralel port - doesn't keep pins states
Hello,
I hope it is the right place to ask about my problem...
I want to use /dev/lp0 (lp module) on my PC for controlling external devices.
The problem is when I wtire 1 byte to /dev/lp0, paralel port keeps this state just for few ms...
(I made special plug - so the is no problem with handshake - details on:
http://www.hut.fi/Misc/Electronics/circuits/nullprint.html)
It is strange because everything works corect on my old PC (Pentium160).
Regards,
Filip
Quoted 12 lines · filip
Hello,
I hope it is the right place to ask about my problem...
I want to use
/dev/lp0(lp module) on my PC for controlling external devices.
The problem is when I wtire 1 byte to/dev/lp0, paralel port keeps this state just for few ms...
(I made special plug - so the is no problem with handshake - details on:
http://www.hut.fi/Misc/Electronics/circuits/nullprint.html)
It's normal, since the parallel -port specification clearly states that the port doesn't maintain the pins voltage more than a minimum mandatory delay, and while setting, the state is undefined.
Quoted 2 lines
It is strange because everything works corect on my old PC (Pentium160).
That was broken hardware, it didn't meet the specifications :))
Quoted 12 lines
Regards,
Filip
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