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adafruit / Adafruit-ST7735-Library

This is a library for the Adafruit 1.8" SPI display http://www.adafruit.com/products/358 and http://www.adafruit.com/products/618
https://learn.adafruit.com/1-8-tft-display
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method to handle tearing effect line does not send the required argument to the display driver #152

Closed ghost closed 6 months ago

ghost commented 3 years ago

According to the documentation of the ST7735R driver, after sending the command, an argument have to be sent later (see page 112). The argument contains one bit that sets how tearing effect line is to be configured. There is no code in the library to send this argument.

https://github.com/adafruit/Adafruit-ST7735-Library/blob/8a3acfeef57f2847671e402299341aa3be8bb91f/Adafruit_ST77xx.cpp#L237

void Adafruit_ST77xx::enableTearing(boolean enable) {
  sendCommand(enable ? ST77XX_TEON : ST77XX_TEOFF);
}

This line is physical and should be connected to the microcontroller in order to be used. There is a bug in the PDF documentation and it is missing in the Block diagram (see page 12). But in the Pad Center Coordinates section of the document it is marked with the name TE (see page 6 and pin number 81). None of the products below have this physical line:

 Works with the Adafruit 1.8" TFT Breakout w/SD card
    ----> http://www.adafruit.com/products/358
  The 1.8" TFT shield
    ----> https://www.adafruit.com/product/802
  The 1.44" TFT breakout
    ----> https://www.adafruit.com/product/2088
  as well as Adafruit raw 1.8" TFT display
    ----> http://www.adafruit.com/products/618
ladyada commented 3 years ago

ok we did test it successfully a while ago, our 1.54" breakout has a TE line - you could submit a tested PR if ya like

ghost commented 3 years ago

I did not check other drivers which this library supports. I'll do it soon. I can send a PR, but I'd prefer to discuss how to design the code first.

enabling requires the flag, disabling does not require a flag;

What do you think of the two methods? One for enabling with a flag as a parameter. One to disable without flag. I am asking because this code is for an Arduino which has its own style. Another problem is a change that won't break people's programs.

I'm thinking of something like that, it should be safe:

Adafruit_ST77xx::enableTearing(boolean mode);
Adafruit_ST77xx::disableTearing();
ladyada commented 3 years ago

best to keep the same function name, can add another argument.