Hi,
I followed another thread (device-tree entry for pwmleds in linux3.12) to get the following device tree in order to activate the ecap pwm on Linux Kernel 3.12 (im using a Beaglebone Black Rev C), I used it to patch am335x-bone-common.dtsi:
am33xx_pinmux: pinmux@44e10800 { pinctrl-names = "default"; backlight_pin_0: pinmux_backlight_pin_0 { pinctrl-single,pins = < 0x164 0x00 >; }; backlight_pin_1: pinmux_backlight_pin_1 { pinctrl-single,pins = < 0x18C 0x03 >; }; backlight_pin_2: pinmux_backlight_pin_2 { pinctrl-single,pins = < 0x188 0x03 >; }; }; pwm_led { compatible = "pwm-leds"; led0 { pwms = <&ecap0 0 50000 1>; max-brightness = <255>; linux,default-trigger = "default-on"; brightness = <127>; }; led1 { pwms = <&ecap1 0 50000 1>; max-brightness = <255>; linux,default-trigger = "default-on"; brightness = <127>; }; led2 { pwms = <&ecap2 0 50000 1>; max-brightness = <255>; linux,default-trigger = "default-on"; brightness = <127>; }; }; ocp { epwmss0: epwmss@48300000 { status = "okay"; ecap0: ecap@48300100 { status = "okay"; pinctrl-names = "default"; pinctrl-0 = <&backlight_pin_0>; }; }; epwmss1: epwmss@48302000 { status = "okay"; ecap1: ecap@48302100 { status = "okay"; pinctrl-names = "default"; pinctrl-0 = <&backlight_pin_1>; }; }; epwmss2: epwmss@48304000 { status = "okay"; ecap2: ecap@48304100 { status = "okay"; pinctrl-names = "default"; pinctrl-0 = <&backlight_pin_2>; }; }; };
However i can only see two pins that output ecap PWM ou Beaglebone Black System Reference Manual:
- Pin 42, GPIO0_7 (MODE 0): eCAP0_in_PWM0_out,
- Pin 28, SPI1_CS0 (MODE 4): eCAP2_in_PWM2_out;
both on Expansion Header P9.
On that question they refer to this pins:
- E18 --> Pinmux mode 0 --> eCAP0_in_PWM0_out
- B19 --> Pinmux mode 3 --> eCAP1_in_PWM1_out
- C18 --> Pinmux mode 3 --> eCAP2_in_PWM2_out
So basically i can only get the first one working fine (Pin 42), the others i can't find or i don't no which pin corresponds to it? can you help me on this? What am i missing?
Another question is, is it not possible to use the eHRPWM instead? As i can understand there can be 3 outputs of these with two channels each, this would be perfect for my application.
Thank you in advance.