High-Definition 480x320 3.5" Screen With Touch and Fonts

This is my first 16-bit parallel screen.

The major issue with this screen —as well as for all other 16-bit parallel screens— is the number of pins required, up to 35:
  • 22 pins for screen, with 16 for data, 5 for command and 1 for backlight PWM, 
  • 6 pins for touch, with 3 for own SPI bus and 2 for interrupt and busy lines,
  • 5 pins for SPI, 3 shared plus 1 per peripheral attached: SD-card reader and EEPROM memory for fonts and icons,
  • 2 pins for power, voltage and ground

The two SPI buses are separated, one fast for flash and EEPROM and another slow for touch.

Connection to Arduino Mega2560

The screen comes with a 2x20 connector and requires an adaptor to fit into the Arduino Mega2560.

Unfortunately, some pins aren't routed, as the RD pin in charge for reading the colour of one given pixel of the screen. This is a serious limitation. 

The adaptor makes the connection from 5V to 3.3V logic levels. Unlike other adaptors, it uses ICs instead of plain resistors
With the help of the adaptor board, connecting the screen to the Arduino Mega2560 is fast. The provided specific library based on the standard UTFT library is well documented and easy to use.

It also works easily with the LCD_screen Library Suite.

Pros

  • Excellent image quality
  • Nice set of fonts and icons on EEPROM
  • Many libraries available

Cons

  • The screen uses many, many pins, even for an Arduino Mega2560.
  • The adaptor doesn't connect all the screen pins, limiting the functionality.

Wrap-Up

  • Excellent image quality
  • Fast display
  • Many pins used

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