Robert: I found a useful article on device tree overlays here: http://www.ofitselfso.com/BeagleNotes/Beaglebone_Black_And_Device_Tree_Overlays.php
After uncommenting the line disable_uboot_overlay_addr3=1 in /boot/uEnv.txt, PWM is working on pin 8_13, even with the Prototype Cape attached. So I believe something in the overlay stored in EEPROM on this particular cape is interfering with PWM. Here is a link to the cape I purchased in case you want to investigate further: https://www.mouser.com/ProductDetail/958-PROCPE-BBBCAPE/ <https://www.mouser.com/ProductDetail/958-PROCPE-BBBCAPE/> Disabling loading of cape’s overlay is a workable solution for me, I am using it only to hold some passive circuits and optocouplers, so I am happy with this approach. Thanks again. Rgds, -Steve Lentz > On Jan 15, 2021, at 2:58 PM, Robert Nelson <[email protected]> wrote: > > On Fri, Jan 15, 2021 at 1:43 PM Steve Lentz <[email protected]> wrote: >> >> I’ve investigated a bit more. First, and I should have done this sooner, I >> removed all the capes I’m using and tested the bare Beaglebone black. >> Success, all four PWMs work. >> >> Then I began adding capes one at a time. I found that when a Prototype Cape >> is used, PWM is no longer available on P8_13. To be absolutely certain, I >> connected a brand new out of the box GHI Prototype Cape. No PWM on P8_13. >> Remove the cape and PWM works. >> >> If I connect a Power Cape, PWM works, this would seem to rule out a bad >> solder joint or something physical on the BBB. >> >> There is nothing near P8_13 on any of these capes, yet something is >> affecting that pin. >> >> Is there something in the device tree that allows the cape to grab one of >> the PWM devices, perhaps for the variable LED that’s on the cape? >> >> Any other ideas what would cause this? > > Do you have a part number for the Prototype Cape used? > > Sorry it doesn't ring a bell for me.. > > 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/8A167D50-C80A-4609-884C-FF74A3715FD7%40gmail.com.
