STM32L073 about LCD Set-up Convertor when setting LCD_VOLTAGESORCE_INTERNAL. The set voltage and measured voltage are different.

[R.K]

Hello Developper Teams.

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I use STM32L073.

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About LCD Setting, The set voltage and measured voltage are different.

​For example,  hlcd.Init.Contrast = LCD_CONTRASTLEVEL_0(2.6V) --> Measured voltage = 3.7V

Is there another place to set it?

​Setting HD=1 dropped it down to 3V, but I can't understand it out.

Is it compatible with LCD specifications?

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Best regard.

[Peter BENSCH]

Is it possible that you have this problem using the NUCLEO-L073RZ?

In this case, you should definitely take a look at the schematics, because there you can see that VLCD (pin 1) is connected to VDD via SB45. Please don't get confused there, because since the underlying board MB1136 is also used for other STM32s, pin 1 has the designation VBAT/VLCD, whereas VBAT is not relevant for the STM32L073.

After desoldering SB45, everything should work as desired.

Regards

/Peter