Re: [beagleboard] Re: PWM Pin Error on Boot
Thanks for the reply John. I'm pretty new to modifying kernel modules and I haven't worked with u-boot at all. I'm not sure at the moment when the GPIO is modified but I think it happens whenever the system resets, most likely on startup. Should I try a kernel dump right after I boot? Thanks, Mike On Wednesday, March 30, 2016 at 2:03:58 PM UTC-7, john3909 wrote: > > Well, that depends on how skilled you are at modifying u-boot and the > linux kernel? > > In each case, modify the code that toggles the GPIO pin by printing text > to the console when the GPIO you want is modified. You could always issue a > kernel dump when that GPIO is modified, which will list the call sequence > that causes the GPIO toggle. For the Kernel, I believe the code you want is > in drivers/gpio/gpio-omap.c, but I haven’t looked at u-boot in a while, but > it should be simple to find the equivalent code. > > If you had a decent JTAG emulator, you could simply set a breakpoint on > the GPIO toggle and then look at the call stack to see which routing is > responsible. > > Regards, > John > > > > > On Mar 30, 2016, at 1:25 PM, M House <mikeh...@gmail.com > > wrote: > > Hey everyone I'm still stuck as to why my beaglebone keeps changing the > polarity to 1 on boot. I can go in and manually change it but it always > resets after reboot. Should I maybe write a start up script to force the > polarity to 0? I'd rather find the root cause rather than a hack but at > this point anything that works is fine by me. > > Thank you > > On Saturday, March 19, 2016 at 11:30:58 PM UTC-7, M House wrote: >> >> I'm doing a project right now that involves using a micro servo. One is >> on port P8_13 and another on P9_14. >> >> Everytime I boot the beaglebone it gives me - error: Error enabling PWM >> controls: Error: ENOENT, no such file or directory >> '/sys/devices/ocp.3/bs_pwm_test_P9_14.15/polarity' >> >> When I check this file it shows a value of '1' inside of it. Where the >> same file for P8_13 shows a zero. When I change the P9_14 polarity file to >> 0 the servo works as intended. I'm really confused why the polarity is >> being set to 1 every time I boot the beaglebone. This also happens if I >> move the servo to P9_16. >> >> I did just upgrade from Debian 7.8 to 7.9 but I don't see how that would >> change the GPIO behavior. >> >> > -- > 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 beagleboard...@googlegroups.com . > For more options, visit https://groups.google.com/d/optout. > > > -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[beagleboard] Re: PWM Pin Error on Boot
Hey everyone I'm still stuck as to why my beaglebone keeps changing the polarity to 1 on boot. I can go in and manually change it but it always resets after reboot. Should I maybe write a start up script to force the polarity to 0? I'd rather find the root cause rather than a hack but at this point anything that works is fine by me. Thank you On Saturday, March 19, 2016 at 11:30:58 PM UTC-7, M House wrote: > > I'm doing a project right now that involves using a micro servo. One is > on port P8_13 and another on P9_14. > > Everytime I boot the beaglebone it gives me - error: Error enabling PWM > controls: Error: ENOENT, no such file or directory > '/sys/devices/ocp.3/bs_pwm_test_P9_14.15/polarity' > > When I check this file it shows a value of '1' inside of it. Where the > same file for P8_13 shows a zero. When I change the P9_14 polarity file to > 0 the servo works as intended. I'm really confused why the polarity is > being set to 1 every time I boot the beaglebone. This also happens if I > move the servo to P9_16. > > I did just upgrade from Debian 7.8 to 7.9 but I don't see how that would > change the GPIO behavior. > > -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[beagleboard] Re: PWM Pin Error on Boot
I should clarify that it is every time I start my node.js server file that a has a required module that uses P9_14. I can manually change the polarity to 0 but it resets every time I reboot. On Saturday, March 19, 2016 at 11:30:58 PM UTC-7, M House wrote: > > I'm doing a project right now that involves using a micro servo. One is > on port P8_13 and another on P9_14. > > Everytime I boot the beaglebone it gives me - error: Error enabling PWM > controls: Error: ENOENT, no such file or directory > '/sys/devices/ocp.3/bs_pwm_test_P9_14.15/polarity' > > When I check this file it shows a value of '1' inside of it. Where the > same file for P8_13 shows a zero. When I change the P9_14 polarity file to > 0 the servo works as intended. I'm really confused why the polarity is > being set to 1 every time I boot the beaglebone. This also happens if I > move the servo to P9_16. > > I did just upgrade from Debian 7.8 to 7.9 but I don't see how that would > change the GPIO behavior. > > -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[beagleboard] PWM Pin Error on Boot
I'm doing a project right now that involves using a micro servo. One is on port P8_13 and another on P9_14. Everytime I boot the beaglebone it gives me - error: Error enabling PWM controls: Error: ENOENT, no such file or directory '/sys/devices/ocp.3/bs_pwm_test_P9_14.15/polarity' When I check this file it shows a value of '1' inside of it. Where the same file for P8_13 shows a zero. When I change the P9_14 polarity file to 0 the servo works as intended. I'm really confused why the polarity is being set to 1 every time I boot the beaglebone. This also happens if I move the servo to P9_16. I did just upgrade from Debian 7.8 to 7.9 but I don't see how that would change the GPIO behavior. -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
