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Maniphest T1179

prototype LCD dimming through PWM
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Description

The LCD controller features brightness control in the chapter 8.2.38. Write Display Brightness (51h) of the datasheet: https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf but it is unclear if that works as expected and has the desired effect.

TVs also allow changing brightness/contrast values but this just alters the color values of what is displayed and does not actually change the backlight intensity.
This needs to be evaluated with the AXIOM Remote LCD.

If it does not have the desired effect we can control the backlight LEDs directly from the PIC32. By using PWM we should be able to implement high frequency dimming.

Schematics: http://files.apertus.org/HARDWARE/AXIOM/BETA/REMOTE/remote_v0.9.pdf
Sheet 3 LED_A1 - LED_A4

sebastian created this task.Apr 20 2020, 9:27 AM
sebastian moved this task from Graphical User Interface to Firmware on the AXIOM Remote board.
sebastian added a subscriber: BAndiT1983.Apr 20 2020, 10:08 AM

@BAndiT1983 has evaluated the ILI9341 backlight control to be working sufficiently well:

ILI9341Display::SetupBacklightControl();

ILI9341Display::SetBacklight(percentage in uint8_t);

BAndiT1983 added a comment.Apr 29 2020, 10:41 PM

Found the link which contains the code i've used for generation of linearization array: https://jared.geek.nz/2013/feb/linear-led-pwm

sebastian closed this task as Resolved.Jan 12 2021, 11:37 PM

@BAndiT1983 did it! 💃