PPS on Raspberry Pi

[Gary E. Miller]

Yo Hal!

On Wed, 26 Jun 2024 20:32:19 -0700
Hal Murray via devel <devel at ntpsec.org> wrote:

> I'm trying to setup a Pi with a GPS hat.
> 
> 
> 
> The Microserver HOWTO says:
> 
> {--config} Edit /boot/config.txt and add these lines to the end of
> the file, replacing 4 with the logical pin number for your HAT if
> it's not an Adafruit:
>   # Get 1PPS from HAT pin
>   dtoverlay=pps-gpio,gpiopin=4
> 
> The first problem is that config.txt and friends have move from
> /boot/ to /boot/firmware/, but I can dance around that.

Uh, maybe for you, but not for my Raspberry Pi distros.

What distro are you on?  I use Gentoo.

> The real problem is that the new/current config.txt says:
>   # Do not modify this file!
>   #
>   # It is automatically generated upon install or update of either the
>   # firmware or the Linux kernel.
> I haven't figured out where to put that line.

I would change distro to Gentoo. :-)

You can change that file, as long as you remember to fix it after
you use their configure tool.  Me, I hate configure tools, and just
prefer to edit the files.

> My notes say to add "pps-gpio" to /etc/modules

Not on arm or arm64.  That is what the dtoverlay does.

> The bits I got from Debian don't have a pps-gpio module.

You will not, you will have an overlay file under /boot somewhere.

> Anybody setup a GPS HAT on a Pi 1 recently?

I just did on a Pi3.  The existing instructions worked fine for
me.


> The link behind "this photograph" is 404

Uh, what link?

> Find "north" on the HAT. It\u2019s the edge that the GPS module is
> closest to, and has a rectangular notch in it (a cutout for a ribbon
> cable). The GPIO header will be 90 degrees clockwise. If this isn't
> clear enough, see this photograph.

Pi HATs only fit one way.  I seem to recall that Pi1 HATS are
not the same as Pi 2, Pi3, Pi4 or Pi 5 HATS.

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

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin
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