Additional pps-gpio

[Gary E. Miller]

Yo Achim!

On Tue, 23 Jan 2018 22:26:07 +0100
Achim Gratz via devel <devel at ntpsec.org> wrote:

> Gary E. Miller via devel writes:
> > Sure it does.  gpsd works with the /dev/ppsX devices, which are
> > kernel timestamped.  I use that on all my RasPi GPS.  
> 
> Yeah.  Now show me how you can get more than one GPIO connected to a
> /dev/pps*,

Dunno, it just works automagically for me:

# ls /dev/pps*
/dev/pps0  /dev/pps1

I plug in two USB GPS and I get two PPS.  Similar for RS-232 serial
ports.

> expecially on the raspberryPi where neither a serial device
> or printer port can provide additional PPS inputs.

Which is why on my RasPi i use GPIO pins.  I know you can use both 
GPI 4 and 18 for PPS.  I suspect that any and all of the RasPi GPIO
pins can work fine.

> Agai, the problem
> is not using multiple such devices, it's with actually getting them
> configured in the kernel.

How about this on a RasPi:

# Uptraonics on gpio 18
dtoverlay=pps-gpio,gpiopin=18
# adafruit HAT
dtoverlay=pps-gpio,gpiopin=4

I use them both, never tried at the same time.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588

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    "If you can’t measure it, you can’t improve it." - Lord Kelvin
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