Re: [Linuxptp-users] MPC8308rdb

[Richard C. <ric...@gm...>]

On Tue, Apr 23, 2013 at 08:16:22AM -0400, Chris LaRocque wrote:
> 
> What would really be convenient is if I can get the tigger input to start
> one of the fiper which would then toggle an alarm pin in one of two modes:
> oneshot or periodic at an arbitrary interval; without interupting the
> processor. I need time stamping of events occuring at rates of 1 kHz or
> greater.

I am not too sure what you meant, but I think the external triggers
(time stamping external signals) should be working fine on your
board. The external time stamps are held in a buffer of size 128,
see drivers/ptp/ptp_private.h. If your application cannot read out all
of the 1+ kHz time stamps on time, then you can increase the hard
coded buffer size.

As far as the fipers go, I think you could fairly easily add an ioctl
to turn them on and off again (or abuse the existing ptp ioctls).
However, the fipers are always in phase with the clock, and the
interval must be an exactly divide 1 Hz (ie integer Hz values only).

It might in fact be possible to program the fipers for arbitrary
periods and phases, but I never figured out how to do it. It was hard
enough getting the 1 Hz and 10 kHz signals working. Freescale's
documents are a bit weak and their tech support is even worse, in my
experience.

HTH,
Richard