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ElectroTechnique / TSynth-Teensy4.1

TSynth for Teensy 4.1
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Cheap ST7735 Color display issues #12

Closed SurvivalHacking closed 3 years ago

SurvivalHacking commented 3 years ago

If a display that appears to be compatible is used, but purchased from inexpensive vendors, such as Aliexpress, there could be malfunction issues. I was able to fix all the problems by making a small change to some definitions in a couple of files.

The first problem is a 1 pixel shift that bends the image. To fix this problem, I modified the function: ST7735_t3::initR in the file: ST7735_t3.cpp

if (options == INITR_GREENTAB) { commandList(Rcmd2green); _colstart = 2; _rowstart = 0; // modified from 1 to 0 by Davide Gatti to fix cheap display

A second problem is the color inversion, to fix this I modified two define in the file: ST7735_t3.h

define ST7735_INVOFF 0x21 // Changed from 20 to 21 By Davide Gatti for cheap display

define ST7735_INVON 0x20 // Changed from 21 to 20 By Davide Gatti for cheap Display

These 2 simple changes fixed the compatible display.

philippejadin commented 3 years ago

would it be use full to provide this as a configurable option somehow ?

SurvivalHacking commented 3 years ago

It seems superseeded by Electrotecnique You need to change the following lines in ST7735Display.h

tft.initR(INITR_BLACKTAB); //INITR_GREENTAB tft.invertDisplay(true); // false

I tested on V2.10 and works fine.

See original post by ET

https://github.com/ElectroTechnique/electrotechnique.github.io/discussions/4