Thanks for the explanation, but could you elaborate a bit more on it? 

As far as I understand the world as it is now works  this way:

0- If you are running anything beyond kernel 4.1 you should be using uboot 
overlays. Be careful to load the latest bb-cape overlays and be sure that 
uboot is the latest version, check via /opt/script/tools/version.sh, 
look for 
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 2015.01-00001-gb2412df]
this is 
wrong:                                                                          
^^^^^^^^^^^^^^^^^^^^^^^^^^
Should be something like:
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 
2017.09-00002-g0f3f1c7907]

If not, do 
/opt/scripts/tools/developers/update_bootloader.sh 
This should put an updated bootloader in the boot block of your Beaglebone. 
Careful: you should have booted from the internal flash, not from an 
external flash-card.

1-Overlays are now loaded in /boot/uEnv.txt at boot time. 
Cape-universal or the other universal capes make it possible to use 
config-pin to configure the pins that you want to use, 
example:
config-pin -l p9-21
gives all the possible settings
config-pin -q p9-21
gives the current setting 
config-pin -a p9-21 i2c
makes the pin respond to i2c signals.

<SPECULATIVE STEPS: DO NOT USE IN THE REAL WORLD:>

2-if another overlay is loaded in /bootuEnv.txt which is not of the 
universal type, config-pin does not work anymore????

3-To find out which overlay is loaded if config-pin does not run, use 
command ?????? to find out which overlay(s) is/are currently running

4-If you want to make a combination of some of the universal settings plus 
an overlay, ??????

</SPECULATIVE STEPS: DO NOT USE IN THE REAL WORLD>

I am pretty sure it's all wrong, but I am struggling with the info too. I 
am trying to modernize gobot to the latest uboot overlay stufff (it is 
still looking for cape_mgr slots file), but it is not exactly clear how I 
can find out if an overlay is set, or if I am able to set a specific pin 
after some overlay has been loaded.




On Tuesday, November 28, 2017 at 6:33:35 PM UTC+1, RobertCNelson wrote:
>
> On Tue, Nov 28, 2017 at 12:45 AM, Ken Shirriff <[email protected] 
> <javascript:>> wrote: 
> > I'm trying to understand the current state of device tree overlays. Is 
> it 
> > correct that the cape manager is now obsolete, and device tree overlays 
> > should be set up through /boot/uEnv.txt? What about config-pin? Is that 
> an 
> > alternative to device tree overlays, or something orthogonal? 
> > 
> > The system I'm using is a PocketBeagle with 4.4.91-ti-r133. Before that 
> I 
> > was using the 3.8 kernel on a BeagleBone and everything seems to have 
> > changed. (Is there a summary somewhere of the new world?) 
>
> Kernel Overlays is obsolete. 
>
> We now use U-Boot Overlays: 
>
> https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays 
>
> config-pin is enabled by default, it allows you to easily change pin's 
> to different functions. 
>
> Regards, 
>
> -- 
> Robert Nelson 
> https://rcn-ee.com/ 
>

-- 
For more options, visit http://beagleboard.org/discuss
--- 
You received this message because you are subscribed to the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/beagleboard/a5ea1ae5-db41-41dd-839e-0cceee13fd34%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to