any one know how to acess pwm slots in /sys/devices/bone_capemgr.9? I try to just change from 8 to 9 and did not work. I use bbb black with ubuntu precise and I cant find /sys/devices/ocp.2/helper.14/AIN7 or /sys/devices/platform/tsc/ain1 those ports are only availible by default in anstrong?
2013/9/2 T.Morgan <[email protected]> > I think most of us have got a single servo running on the BBB by now. Has > anyone succeeded in using 3 or more PWM channels at the same time? > > I find that if I: > > $ echo am33xx_pwm > /sys/devices/bone_capemgr.8/**slots > $ echo bone_pwm_P8_13 > /sys/devices/bone_capemgr.8/slots > $ echo bone_pwm_P8_19 > /sys/devices/bone_capemgr.8/slots > $ echo bone_pwm_P9_14 > /sys/devices/bone_capemgr.8/slots > $ echo bone_pwm_P9_16 > /sys/devices/bone_capemgr.8/slots > > Then directories /sys/devices/ocp.2/pwm_test_P8_13.xx and > pwm_test_P9_14.xx contain the expected files and subdirectories: > > driver duty modalias period polarity power run subsystem uevent > > while directories /sys/devices/ocp.2/pwm_test_P8_19.xx and > pwm_test_P9_16.xx only contain: > > modalias power subsystem uevent > > The uevent files for P8_13 and P9_14 both contain the line > 'DRIVER=pwm_test' which is missing from the uevent files for P8_19 and > P9_16. > > The output on pins P8_13 and P9_14 behaves as expected when I write to > their period and duty files. > > Pins P8_19 and P9_16 are fixed high or low (depending on the history of > tests run on them). > > If I reverse the order in which I load the PWM modules, P8_19 and P9_16 > are good, P8_13 and P9_14 are bad. > > I notice that after loading the PWM module on, say, P8_13, the output on > the second pin for that EHR, P8_19 immediately goes high. > (This may be indicative of the driver messing up the 2nd channel while > configuring the 1st.) > > Very occasionally, a second PWM channel can be opened on one of the EHRs. > When this happens, writes to the channel's period file return error > 'invalid argument'. > > I've observed the same behavior on Angstrom 6/20 and 8/21 (in desperation > I downloaded a copy from the developer's site). > I've tested this with the PWM pins unconnected, connected to LEDs through > serial resistors, connected to a 7404 and connected to L293Ds. > I've tested this with the Adafruit BBIO library (0.17), shell commands as > above, and using a homebrew python SYSFS front-end. > > Is there a bug in the test_pwm driver or am I missing some step in > initializing the PWM channels? > > -- > 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]. > For more options, visit https://groups.google.com/groups/opt_out. > -- Marcus de Vasconcelos Diogo da Silva "Uma montanha até um cego consegue desviar,mas é nas pedras menores que nós muitas vezes tropeçamos e caimos!" -- 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]. For more options, visit https://groups.google.com/groups/opt_out.
