ESP12F PCF8574 and LCD 20x4

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1

Hi to all, Im using Wemos D1 pro with LiquidCrystal_PCF8574 library and Im trying to use LCD 20x4 HD44780, but nothing is being shown in the LCD. Im able to display on LCd16x2 but this library is not working in the 20x4.
I tried the other library "LiquidCrystal_I2C.h" but as Im using the ESP12F a warning message is display about not using avr board and some errors that are not displayed if I use the PCF8574 library. For example this throws error:

int LastButtonS = LOW;

Complain about "LOW" not recognize.
Which library should I use to work with the 20x4 LCD and ESP12F?
Regards
Gaston

2

these warnings are not crucial. The sketch should still work.

If you want to use another library you can try mine:
https://werner.rothschopf.net/202009_arduino_liquid_crystal_i2c_en.htm

It's main focus is to get a easy print of special characters and it should work on an ESP with a 20x4 right away. Start with the examples in the PCF8574 folder:

forum_liquidcrystal
forum_liquidcrystal842×414 11.5 KB

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Power the display with 5V and connect pullups to 3V3. If the 5V is a bit light but no less then 4.5V that will not hurt. The reason the I2C ports have protection diodes to VCC so pulling up to 5V on a 3V3 device will forward bias them and potentially damage the port.

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The best library for I2C enabled hd44780 controlled LCDs is the hd44780 library. The library will automatically determine the I2C address and the LCD to I2C pin mapping. No other hd44780 library will do that. Install the hd44780 library using the IDE library manager. For that LCD use the hd44780_I2Cexp class. There is extensive documentation and examples included with the library.

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