1 pps input pin on beaglebone black

[Thomas Remmert]

Hello,

I am semi new at using the BBB, and am finding a lot of conflicting information on the web regarding gpio pins and their use.  My goal here is to input a 1pps signal into the BBB for time sync using ntp.  I have found several tutorials online, but they all talk about using a custom overlay.  I am not sure if this is old information and am I supposed to use the config-pin utility? 

Ultimately, I am trying to read in NMEA (gps) time info along with the 1pps signal.  I am also trying to use two ADC's as inputs and use 4 GPIO pins as outputs.  Does this require a custom DTS overlay or do I use the config-pin utility?

Thanks for the clairificaiton

[Robert Nelson]

Use an overlay, or patch your main *.dtb for pps device tree node..

here's one example i did with the PocketBeagle + GNSS 5 click

https://www.mikroe.com/gnss-5-click

https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/PB-UART4-GNSS-5-CLICK.dts

Regards,

--
Robert Nelson
https://rcn-ee.com/

[Robert Nelson]

On Mon, Jun 25, 2018 at 11:56 AM, Thomas Remmert
<trem...@snaggleboards.com> wrote:
> Very cool.... Wish I knew about the GNSS 5 click before!
>
> Just for further understanding, if I were to apply the DTS file that
> you linked to, would that "disable" all other pins on the board? For
> example, if I loaded your DTS file, would my other ADC pins (that I
> currently use) stop working? If so, I assume I would need to load two
> overlays?

With the PocketBeagle, "cape-universal" is built-into the base *.dtb..
For the BeagleBone Black, this will be the default for v4.16.x+

So for the BeagleBone Black, with a less then v4.16.x based kernel,
you don't need to 'disable' the taken pins, just define and use them.

An overlay, doesn't have to be "one" node, you can combine all your
modifications into one overlay aka pps and adc pins..

[Thomas Remmert]

Sounds good. Ill do some research on creating my own overlay.

Lastly, is the config-pin utility outdated and not needed anymore?
Seems that I am finding lots of tutorials that either utilize that
application or the device tree overlays. Just want to make sure I am
focusing on the correct method..

--
Thomas Remmert
Cell: 936-647-6030
Office: 281-203-0855

[Robert Nelson]

On Mon, Jun 25, 2018 at 12:27 PM, Thomas Remmert
<trem...@snaggleboards.com> wrote:
> Sounds good. Ill do some research on creating my own overlay.
>
> Lastly, is the config-pin utility outdated and not needed anymore?
> Seems that I am finding lots of tutorials that either utilize that
> application or the device tree overlays. Just want to make sure I am
> focusing on the correct method..
>

config-pin is more for the prototyping phase.. aka, let's try this
wired here and test it..

Where-as the overlay is more... I've built an adapter card, and just
want it configured on bootup.