On Wednesday 22 July 2009 3:31:54 pm Alexander Best wrote: > the ppi manual states that using ioctl with /dev/ppi is extremely slow. i need > the parallel port to be really fast. i need to communicate with a device that > uses asynchronous transfer at a rate of ~ 2 mhz. so i need the full ISA bus > speed to be able to push/pull data to/from the parallel port without any > delays. timing is really critical. if there's a lot of work to do for the > scheduler and the io calls get queued too long the transfer will fail.
The overhead of ppi is probably in the noise on a modern CPU. I think you should be fine with just using ppi(4). > actually i meant: how can i check the available parallel ports from within my > app? is there a syscall i can use or something like that? You can look for ppcX devices perhaps. The easiest way might be to enable ppi and look for /dev/ppiX devices in /dev. -- John Baldwin _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
