On 2012-01-21, Uwe Klein <[email protected]> wrote: > Hal Murray wrote: >> In article <[email protected]>, >> unruh <[email protected]> writes: >> >>>Further to my kernel pps problems. I have now managed to get pps-ldisc >>>which is supposed to timestamp the serial port DCD transition interrupt, >>>and the pps_parport. In the case of the latter I was wondering if anyone >>>has any idea of how it works. The on board parallel port interface on >>>old motherboards used the edge transition to signal the interrupt. This >>>would mean that once the routine had serviced the interrupt, no other >>>one would occur until that next edge. However, for the add in parallal >>>cards, they use shareable, level triggered interrupts. Since the input pulse >>>is >>>many ms long, this means that the interrupt keeps triggering about once >>>every usec as long as the ack line is up. >>>Does anyone know if the pps_parport module treats such shareable >>>interrupts correctly? >> >> >> Usually, that sort of hardware has a way to turn off the interrupt. >> It's something like you write a bit in a register to "ACK" that >> interrupt. When the external signal turns off, it clears that bit. >> >> The info should be in the fine print if you can get a good data sheet. >> > The interrupt controller works differently. > you switch from edge triggered to level triggered.
Not sure what you mean by this. > > uwe _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
