SanCloud BBE and P8-10

[Daniel Kulp]

I've been testing my apps/capes with a couple of the SanCloud BBE devices to see how they work and did run into a little problem.   I contacted SanCloud and they confirmed that P8-10 on the BBE is a "no connect".   This is documented on their web site (see pin mapping section of https://www.sancloud.co.uk/?page_id=254 ) but I completely missed it. 

In any case, cape-universal and such still shows the pin as configurable and config-pin and such can be used to set the pin as gpio out and such.  Is still appears in /sys/class/gpio/.  Etc...  It just doesn't work as it's a no-connect.  The question is:  should the device tree or whatever remove that pin on the BBE?  For me, it was confusing as, from the OS level, it looks like it should work and it looks like I can configure it and use it, but then it didn't work.   However, on the flip side, my C++ code would have crashed (poor programming on my side) if the stuff in /sys wasn't there as I kind of assumed on the BBB's that it's there.     I can definitely update my code (working on that), but the question does remain: should the devices that cannot work exist in the tree?

[Robert Nelson]

On Sat, Feb 9, 2019 at 10:38 AM Daniel Kulp <d...@kulp.com> wrote:
>
> I've been testing my apps/capes with a couple of the SanCloud BBE devices to see how they work and did run into a little problem. I contacted SanCloud and they confirmed that P8-10 on the BBE is a "no connect". This is documented on their web site (see pin mapping section of https://www.sancloud.co.uk/?page_id=254 ) but I completely missed it.
>
> In any case, cape-universal and such still shows the pin as configurable and config-pin and such can be used to set the pin as gpio out and such. Is still appears in /sys/class/gpio/. Etc... It just doesn't work as it's a no-connect. The question is: should the device tree or whatever remove that pin on the BBE? For me, it was confusing as, from the OS level, it looks like it should work and it looks like I can configure it and use it, but then it didn't work. However, on the flip side, my C++ code would have crashed (poor programming on my side) if the stuff in /sys wasn't there as I kind of assumed on the BBB's that it's there. I can definitely update my code (working on that), but the question does remain: should the devices that cannot work exist in the tree?

I didn't realize P8_10 is a No Connect on this board.

Regards,

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