[PARPORT] overhead?

Kev (klmitch@mit.edu)
Fri, 04 Jun 1999 12:25:15 EDT

I've run across plans for a simple device that connects to the parallel port
and generates DMX, which is a theatrical lighting control system. The
device as designed, however, requires a continuous stream of bytes; thus, I
would have to send a new byte to the parallel port every 32 us. This
obviously can't be done with a timer; my question is, assuming I use
interrupt-driven IO for this, how bad would the overhead be? I'm assuming
that the interrupt handler would only frob_control twice to strobe a data
byte into the device and mark a bh that would deal with getting the next
byte and writing it to the port in preparation for the next ACK. What other
problems would I run into?


Kevin L. Mitchell <klmitch@mit.edu>
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