Help with i2c screen that only show black squares

[EphraimElgrabli]

I recently bought a new display for my project to replace the ST7789 screen I had before. I specifically purchased this screen, which seems to be supported: AliExpress Link
However, I'm experiencing an issue. When I plug the power cable into the Raspberry Pi Zero W 2, the screen boots up but only shows black squares. I've checked if the Pi is faulty by running RetroPie with an HDMI signal, tested several SD cards formatted to FAT32, and checked my soldered pins multiple times. I've also configured the INI file with all possible communication addresses (0x20 - 0x27), but still have had no luck.
Can you help me troubleshoot this problem? Thank you in advance.

[craigyjp]

What's your config file look like, have you configured it for i2c, usually white squares is a contrast issue.

Also is it connected to +5v or +3.3v

[craigyjp]

On the pi you really only need the i2c line in the config for the address, the data lines for LCD are not required.

The sda and scl pins should connect to your i2c interface along with +5v and ground.

[EphraimElgrabli]

Ok I will try this approach, thank you so much!

[craigyjp]

Read this section regarding LCD and back packs there are two address ranges...

https://github.com/probonopd/MiniDexed/wiki/Hardware

[diyelectromusic]

That doesn't look right for an i2c connection, it does for an standard parallel interface, but i2c is different.

If LCDI2CAddress is defined then the other entries are ignored. LCDEnabled does still need to be set to 1 though.

And yes, the two ranges for these devices. If it uses the PCF8574 chip then the range is 0x20-0x27 (0x27 usually the default) or 0x38-0x3F (0x3F as default) for devices with a PCF8574A.

Kevin

[craigyjp]

According to the AliExpress link it's a T variant of the chip, I don't know what that means to addressing, if he connects it to the esp32 and scans the i2c bus it should show it's address.