On Wed, Feb 21, 2018 at 7:44 PM, James Fitzsimons <[email protected]> wrote: > Hi all, > > I'm trying to use the PWM outputs on my beaglebone and have a question about > working out which pwmchip device a pin maps to. > > After figuring out the steps to get the PWM overlays working with u-boot (as > most tutorials are still referring to cape manager), I was struggling with > getting a PWM output working using standard shell commands (echoing values > to duty_cycle, period, enabled etc.) I came across this nugget of > information on a blog post: > > "EHRPWM1 is under PWMSS1 which has address 0x48302000 and can be seen > under pwmchip0." > > When I list the contents of my /sys/class/pwm directory I get the following: > > root@beaglebone:/sys/class/pwm# ls -la > total 0 > drwxrwxr-x 2 root pwm 0 Jan 1 2000 . > drwxr-xr-x 59 root root 0 Jan 1 2000 .. > lrwxrwxrwx 1 root pwm 0 Nov 3 2016 pwmchip0 -> > ../../devices/platform/ocp/48300000.epwmss/48300100.ecap/pwm/pwmchip0 > lrwxrwxrwx 1 root pwm 0 Nov 3 2016 pwmchip1 -> > ../../devices/platform/ocp/48300000.epwmss/48300200.pwm/pwm/pwmchip1 > lrwxrwxrwx 1 root pwm 0 Nov 3 2016 pwmchip3 -> > ../../devices/platform/ocp/48302000.epwmss/48302200.pwm/pwm/pwmchip3 > lrwxrwxrwx 1 root pwm 0 Nov 3 2016 pwmchip5 -> > ../../devices/platform/ocp/48304000.epwmss/48304100.ecap/pwm/pwmchip5 > lrwxrwxrwx 1 root pwm 0 Nov 3 2016 pwmchip6 -> > ../../devices/platform/ocp/48304000.epwmss/48304200.pwm/pwm/pwmchip6 > > Note that in my system the device that maps to 0x48302000 is actually > pwmchip3, not pwmchip0 as in the blog post. Once I established that I got > things working. > > My question is - where do I find the information that tells me that EHRPWM1 > is under PWMSS1 which has address 0x48302000? I've had a hunt through the > am3358 datasheet and can't see it there. Can anyone point me in the right > direction please?
Here you go: https://github.com/beagleboard/bb.org-overlays/blob/master/examples/cape-unversal-pwm.txt#L13-L18 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/CAOCHtYgXQ3sNd%2BOmdy4T5a9Zj-9e8G_63AhnU0hmt3orGZcqew%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
