AVRTFT

Simple project to drive a TFT LCD with an AVR MCU (ATmega328P) and avr-libc.

Currently supported displays/drivers:

• Adafruit 1.8" Color TFT LCD 160x128 ST7735R
• Adafruit 2.0" Color IPS TFT 320x240 ST7789
• Adafruit 2.8" Color TFT LCD with Cap Touch 320x240 ILI9341

Currently implemented features:

• Mostly complete UTF-8 set (code points U+0000 to U+00FF) of Hack font
  with antialiasing (4-Bit greyscale)
• Some emojis (16-Bit RGB)
• Write text in Hack including emojis 🙂
• Draw bitmaps
• Write text and bitmaps via USART
• Upload BMP images via USART (16-Bit 5/6/5 RGB)
• Process touch events (FT6206)
• Very basic paint application
• Logging via USART

The AVR is clocked with a crystal for reliable communication via USART.

RAM usage currently is 210 bytes. Program memory is fully used, mainly by
font and emoji bitmaps.

Ideas:

• Read pictures from SD Card
• Display 4K@50Hz videos...

Write something via USART

Connect to the controller with for example GTKTerm (38400 Baud).
Write some text and a bitmap, and upload a BMP image:

c 0xffff // clear display
d // display the demo
t 0 0 Just some text // write text in Hack to row 0 column 0
b 0 0 1 // write bitmap with index 1 (tiny Linus cat) to row 0 column 0
p 0 0 // prepare to "stream" a 16-Bit (5/6/5) RGB BMP image to row 0 column 0
cat Bali160x128.bmp > /dev/ttyUSB0 // upload a BMP image

Enter emojis

Emojis are entered with a tabulation char + their "code", i.e. Smile!<TAB>s for a smiling emoji.

Paint application

A super basic paint application created to learn about processing touch events
and draw something on the screen.

The FT6206 based touch screen of the
Adafruit 2.8" Color TFT LCD with Cap Touch 320x240 ILI9341
works quite well but at least for me the coordinates of touches close to the
long edges of the screen are a bit off (too close to the edge) and there seems
to be no calibration capability - the data sheet mentions "auto calibration".

But still it is fun and it should be possible to create an application
supporting touch with reliable usability.