> Thanks, Folkert, that's most helpful! One thing which is unclear to > me is what do you mean by pin 8? Is that a programming number, or > does it refer to the GPIO header? I did try and find this in the > RPi documentation, but it's not clear.
Check this picture: http://jeffskinnerbox.files.wordpress.com/2012/11/raspberry-pi-rev-1-gpio-pin-out1.jpg GPIO pin 8 is in the upper right block with SPI in it. GPIO 8 (CE0) is written above it. By the numbering on that diagram it is physical pin 24. > I'm currently using NTP driver type 22 on the RPi I would like to > test with. If I move to the type 28 driver it doesn't matter that > PPS is left supported in the Linux kernel. Please confirm there is > no need to revert to a kernel without PPS support. Is there a > simple way of stopping the OS stealing that GPIO pin - turning off > PPS support with a simple edit? If I remember correctly, the kernel patch uses GPIO 18 (PCM_CLK), so using GPIO 8 will work fine with the patched kernel. > What might matter, of course, is that I would need to move the > actual PPS signal to a different pin as kernel-PPS and your program > would not live together, as both would want to grab that pin. So it > may mean making a small hardware change as well if I can't turn off > PPS support. Maybe, but I'm not an electronics expert (not at all in fact) you can feed both pins? > One thing you might want to try is to pulse one of the GPIO pins in > response to the rising-edge interrupt you get, to see what the delay > is when measured by a 'scope. Ok, I've uploaded version 0.2 which can do so. This version can also, in debug mode, show the offset of the local clock to the PPS timestamp. Folkert van Heusden -- Nagios user? Check out CoffeeSaint - the versatile Nagios status viewer! http://www.vanheusden.com/java/CoffeeSaint/ ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
