M5-TOUGH / unable to change display brightness

erazor

Hi.

I'm using the latest library via Platformio (lib_deps = https://github.com/m5stack/M5Tough) and am unable to change the display brightness.

My code is as simple as this:

M5.Axp.SetLcdVoltage(2500);

This does not change anything on the display.

It works with the M5-Core2 module though.

Can anybody confirm the SetLcdVoltage works for the M5-TOUGH?

Thanks and have a great week.

flypeek

no M5-Core to try
https://github.com/m5stack/M5Tough/blob/master/src/M5Display.h

class M5Display : public TFT_eSPI {
    public:
      static M5Display* instance;
      M5Display();
      void begin();
      void sleep();
      void wakeup();
      void setBrightness(uint8_t brightness);
      void clearDisplay(uint32_t color=ILI9341_BLACK) { fillScreen(color); }
      void clear(uint32_t color=ILI9341_BLACK) { fillScreen(color); }
      void display() {}

so you can try this

#include <M5Display.h>

M5.Lcd.setBrightness(value);    //uint8_t  Brightness (0: Off - 255:Full)

erazor

Hi.

No Luck with M5.Axp.SetLcdVoltage(...);
The value has to be from 0-255 anyway.

At the backside they mentioned the backlight:
"BL: ACP_LDO3"

So this seems to the same as in Core2.

teastain

@erazor I have an "always on" project using Core Basic. I use
M5.Lcd.setBrightness(75); //75 is high
and
M5.Lcd.setBrightness(10); //10 is low
Works well, you can try different values to suit.
-Terry
P.S.
My other application runs on a Core2 and I use:
if (enable) {
M5.Axp.SetLcdVoltage(2900); //3000 very bright
} else {
M5.Axp.SetLcdVoltage(2600); //2500 way too dark, 2600 very dim
}

erazor

Well, yeah... but nothing works with the M5-TOUGH which should support it via the Axp.

felmue

Hello @erazor

have a look at the AXP192.cpp where SetLDOVoltage() is used to manipulate LDO3 (aka brightness). Use it like below in your code.

M5.Axp.SetLDOVoltage(3,3000);

Thanks
Felix

erazor

@felmue said in M5-TOUGH / unable to change display brightness:

M5.Axp.SetLDOVoltage(3,3000);

Hi Felmue!

That one works, thanks a lot!

Really confusing that there is a PWM backlight LED mentioned in the library which does not work. And that the usage of SetLcdVoltage is inconsistent between the Core2 and TOUGH.

On Core2 the LcdVoltage changes DCDC3 (@param number 0=DCDC1 / 1=DCDC2 / 2=DCDC3 ) which is connected to LCD_BL. For the TOUGH on the other hand DCDC3 is unused and they used the LDO3.

So maybe they should simply change the line SetDCVoltage(2, voltage); to M5.Axp.SetLDOVoltage(3,voltage); or maybe even better introduce a new function SetLCDBacklightVoltage(...) in their library.

Thanks to all for your hints.