PWM not working in pins P9_14 & P9_16 in BBB

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1

Hi all,

I have already configured the pins P9_21 and P9_22 for PWM function using

BB-PWM0 overlays.

But now I want to use these pins as UART and some other pins as PWM.

I tried to make P9_14(EHRPWM1A) & P9_16(EHRPWM1B). For this I used the overlay BB-PWM1.

A part of BB-PWM1-00A0.dts is shown here to confirm that BB-PWM1 corresponds to P9_14(EHRPWM1A) & P9_16(EHRPWM1B).

fragment@0 {

target = <&am33xx_pinmux>;

overlay {

pinctrl_spec: Panel_Pins {

pinctrl-single,pins = <

0x48 0x06 /* (U14) gpmc_a2.ehrpwm1A */

0x4c 0x06 /* (T14) gpmc_a3.ehrpwm1B */

;

};

};

};

This is creating a folder pwmchip4 in /sys/class/pwm directory.

Then with the following commands, pwm0 and pwm1 are created in /sys/class/pwm/pwmchip4 directory.

sudo echo 0 > /sys/class/pwm/pwmchip4/export

sudo echo 1 > /sys/class/pwm/pwmchip4/export

And software written same as in the case of P9_21 and P9_22.

But PWM signals are not appearing in P9_14(EHRPWM1A) & P9_16(EHRPWM1B).

I tried also P8_13(ehrpwm2B) & P8_19(ehrpwm2A) in the same way with BB-PWM2 overlay.

This is creating a folder pwmchip2 in /sys/class/pwm directory. These are also not working.

I think I am missing something.

Please help me to find out a solution.

Thanks in advance for the help.

Thanks & Regards,
Sajeevan.K

2

Hi all,

Let me make my question short.

I could configure the pins P9_21 and P9_22 as PWM output using BB-PWM0 overlay.
But why it is not possible configure the the pins P9_14 & P9_16 and P8_13 & P8_19 as PWM signals, by doing the same procedure with BB-PWM2 and BB-PWM1 overlays?

Thanks & Regards,
Sajeevan.K

3

Hi all,

Now I could make P9_14 working as PWM, with a Python script importing Adafruit_BBIO.PWM.

But for this to work, I need to enable the below line in uEnv.txt

cmdline=coherent_pool=1M net.ifnames=0 quiet cape_universal=enable

But enabling this line will make my other applications(including UARTs, I2Cs) not working.

Any way to make all things working?

Thanks & Regards,
Sajeevan.K