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Bodmer / TFT_eSPI

Arduino and PlatformIO IDE compatible TFT library optimised for the Raspberry Pi Pico (RP2040), STM32, ESP8266 and ESP32 that supports different driver chips
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readRect and pushRect don't work! #134

Closed pbecchi closed 6 years ago

pbecchi commented 6 years ago

I am trying to move a screen 20x20 area to another screen point. All what I get is a black square! I am using a 3.5 RPi ili9486 SPi Tft. The code look like this: int16_t data[400]; tft.readRect(100,100,20,20,data); tft.pushRect(150,150,20,20,data);

Bodmer commented 6 years ago

The RPi TFT is write only and does not permit reading of the CGRAM. This is a limitation of the RPi screen design.

The readRect() works OK with ILI9341 SPI and UNO style 8 bit parallel displays.

I hope to find time to write a user manual for the library but I am very busy with paid work at the moment!

pbecchi commented 6 years ago

Thanks...a manual coul be very usefull....does ili9488 allow reading CGRAM?

Bodmer commented 6 years ago

Yes, but the TFT driver can be configured for bidirectional SPI or separate MISO and MOSI signals so it is a bit hit and miss when ordering a display. I have not got it working at all on some displays, possible due to some timing issue or undocumented display configuration made at PCB level.

The only displays I have tested the reading of CGRAM are the ILI9341 SPI and ILI9481 8but parallel displays. Reading the CGRAM on an SPI display is very slow. I recommend using an UNO style ESP32 and UNO style TFT if reading CGRAM is a must have feature for your sketch.

pbecchi commented 6 years ago

Ok thanks again .....I will make some trial and let you know the results. I want to create a pop-up windows, so I need to save and restore the background, I cannot think any 9ther method!

Where a can find how to configure bidirectional SPI? It should not be by default?