[time-nuts] 10MHz LTE-Lite - PPS accuracy?

Paul tic-toc at bodosom.net
Wed Dec 10 16:20:17 EST 2014


On Wed, Dec 10, 2014 at 3:37 PM, Hal Murray <hmurray at megapathdsl.net>
wrote:
>
> Linux has two APIs to PPS.
>

I'm using gpsd 3.9 which uses PPS-API if available.  It pushes LD 18 and
just like using ldattach there's no output.

Both result in:

[ 7668.796593] pps pps1: new PPS source usbserial0
[ 7668.796624] pps pps1: source "/dev/ttyUSB0" added

and the creation of (in this case) /sys/devices/virtual/pps/pps1.

There are no events though.

...Support for USB serial
> devices is not so good.
>

Yes, I read something that suggests that not all chipsets are supported by
the DCD patch to the USB serial driver.

I think I've lost interest again.  I'll just run the PPS into a gpio pin.
But if anyone does get USB-DCD working with Linux I'd appreciate any
details.

Thanks.


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