PWM for the Arduino Giga Display Shield

Arduino Boards
1

I’m trying to control the backlight of my Arduino Giga Display Shield. By default it works in the on/off fashion:

# init the lcd display
lcd = display.DSIDisplay(framesize=display.FWVGA, portrait=True, refresh=60, controller=display.ST7701(),)

It works to switch the backline off and on as follows:

lcd.backlight(0) # off
lcd.backlight(100) # on

however, the openMV documentation and also the display shield diagrams mention a PWM capability, if I understand well on pin PB12, which is not a gpio (?).

If I try to use the constructor for a PWMBacklight as documented on pin ‘PB12’ I get an error that pin ‘B12’ (note the missing ‘P’) is not allowed on timer 3.

*class* display.PWMBacklight(*pin* , *timer=3* , *channel=3* , *frequency=200* )[¶](https://docs.openmv.io/library/omv.display.PWMBacklight.html#display.display.PWMBacklight)

Anyways, I don’t get it. Any tips or pointer? Thanks!

2

PB12 doesn’t support timer3:

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The PWM circuit they used supports 1-wire though:

ENA2184-D-260345.pdf

3

excellent, thanks. i’ll look into that - new challenge! this is a side project, will take some time. if i get it working, I will share. cheers!