EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Denge on December 12, 2024, 01:25:03 pm
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Hello All,
I'm struggling with adjusting the brightness of the ILI9488 display.
I used the "Write Display Brightness Value (51h)" and the "Write CTRL Display Value (53h)" command but nothing changes :-(
Anyone an idea how to correctly adjust the brightness of the display?
Thanks for helping.
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The backlight might be driven completely separately, with the ILI9488 having no control over it.
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What are these commands then used for??
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They are used for controlling the backlight brightness, if the required PWM mosfet has been fitted on the board and the PWM_OUT pin is connected to it.
It would help knowing if you are using a bare panel and it's model or if it is some module.
If it is a module and there is two separate terminals (LED+&LED- or LED_K & LED_A) for the backlight led, then ILI9488 likely has no control over it.
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This is the module I have, with the touchscreen chip populated although.
Strange that I can't adjust the brightness on this one!
Are there other commands involved influencing the "Write Display Brightness Value (51h)" command?
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I see a pin labeled 'LED' on the header, so you might need to use that to control the backlight. A lot of LCD controllers like the ILI9488 can control the panel backlight, but that does not mean the panel manufacturer built it that way. Although there may be another control register to enable/configure the brightness control that you need to mess with.
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Yes, most of these boards do not connect the backlight PWM pin of the controller IC to the transistor driving the backlight LEDs of the panel, and the PWM pin is rarely made available either, so that's typically not something you can do by simple wiring. I'm afraid you'll have to PWM the BL signal yourself.