iMX6: can the power-up state of PWM be low?

Our Colibri iMX6 controls the brightness of some panel LEDs using PWM B. This is all fine and works well. The maximum brightness a user can set results in a 75% PWM duty cycle, and this is actually pretty bright.

However, on power-up PWM B starts off as high, and remains like that while the OS boots and the application loads. This makes the LEDs way too bright during this period.

Is there any way to have PWM B power up low? We would prefer to avoid adding any additional components to control this.

At boot loader stage you can configure that pin as a GPIO and set it to 0.
See details here - https://developer.toradex.com/knowledge-base/gpio-config-block-settings#iMX6

Well that was easy. This is what I did:

Press [SPACE] to enter Bootloader Menu

Initiating image launch in 2 seconds.


BootLoader Configuration:

C) Clear Flash Registry
X) Enter CommandPrompt Mode
D) Download image to RAM now
F) Download image to FLASH now
L) Launch existing flash resident image now


Enter your selection: x

>set pin.28.ctrl=1

>set pin.28.direction=1

>set pin.28.level=0

>save pin
16 sectors of configuration data stored to boot.

It appears to have the desired effect: Pin 28 of Iris connector X16 now powers up low.

Cool. Thanks!

I’m glad that it works for your. Thanks for the feedback