LED dimm with gpio-pwm

Posts: 101
Joined: Thu Dec 04, 2014 6:31 am

Re: LED dimm with gpio-pwm

Fri Jan 09, 2015 11:52 pm

Hey Ton, sorry for my late response. First of all - what do you mean with "before" and "after"?

So far Timer 0 is not running at all. Timer 1 is running - as watchdog timer.
I am not sure regarding my theory of system tick counter is been used for PWM - anyway, are you having the same problem if you use periods > 200 ms?

If you share the program, i can analyze it on my scope during the weekend!
Buy now - breakout board for VoCore to easy adapting your idea!

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Posts: 22
Joined: Sun Nov 16, 2014 4:35 pm

Re: LED dimm with gpio-pwm

Sat Jan 10, 2015 8:40 am

With before/after I mean this set of commands.
Basically it is to start a signal on the output.
The period and duty value can vary.

Code: Select all
mkdir -p /config
mount -t configfs none /config
mkdir /config/gpio_pwm/21
echo 1 > /sys/class/pwm/gpio_pwm\:21/export
echo 10000000 > /sys/class/pwm/gpio_pwm\:21/period_ns
echo  5000000 > /sys/class/pwm/gpio_pwm\:21/duty_ns
echo 1 > /sys/class/pwm/gpio_pwm\:21/run

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