C Library for ST7789 1.69 TFT LCD display

ST7789 Description

Detailed information are described in Datasheet ST7789V2. Initialization is the same as for ST7735 driver.

Library

C library is aimed for driving 1.69 TFT LCD display 320x240 with ST7789 driver through SPI's Atmega328P / Atmega8.

Versions

• 1.0 - the first publication, init sequence and basic functions like draw line, clear screen, draw char, draw string.

Initialization

// +---------------------------+
// |        Power UP           |
// +---------------------------+
// |      delay >  10ms        |
// +---------------------------+
//              |
// +---------------------------+
// |      Hardware Reset       |
// |         IMPULSE           |
// +---------------------------+
// |        | >10us | >120ms   |
// | _______         ________  |
// |        \_______/          |
// |                           |
// +---------------------------+
//              |
// +---------------------------+
// |   Software Reset / 0x01   |
// +---------------------------+
// |       no argument         |
// |      delay > 120ms        |
// +---------------------------+
//              |
// +---------------------------+
// |    Sleep Out / 0x11       |
// +---------------------------+
// |       no argument         |
// |      delay > 120ms        |
// +---------------------------+
//              |
// +---------------------------+
// |    Pixel Format / 0x3A    |
// +---------------------------+
// | Color mode RGB565 / 0x55  |
// |      delay >  10ms        |
// +---------------------------+
//              |
// +---------------------------+
// |    Invert Color / 0x21    |
// +---------------------------+
// |       no argument         |
// |      delay >  10ms        |
// +---------------------------+
//              |
// +---------------------------+
// |    Display On / 0x29      |
// +---------------------------+
// |       no argument         |
// |      delay > 120ms        |
// +---------------------------+

Hardware connection MICROCONTROLLER -> LCD

Library was tested with ST7789 1.69″ TFT Display and Arduino UNO R3. The Arduino was without a bootloader installed, it was only raw Atmega328P microcontroller. Communication was done through SPI port interface of Arduino UNO R3. This hardware configuration was chosen for simplicity.

PORT LCD	PORT ATMEGA328P	ARDUINO UNO R3	Description
UCC	+5V	+5V	Supply Voltage +5V
GND	GND	GND	Ground
CLK	PB5	D13	SPI Serial clock signal
DIN	PB3	D11	SPI Serial data in / MOSI
CS	PB2	D10	SPI Chip Select
BL	PB1	D9	Backlight control
RST	PB0	D8	Chip Reset Signal
DC	PD7	D7	SPI data / command; 1=Data, 0=Command

Picture of hardware connection

Usage & Tested

Library was tested and verified with ST7789 1.69″ TFT Display and Atmega328P. It can be used for MCU Atmega8 too because of the similarity with Atmega328P.

Demonstration

Links

• Datasheet ST7789
• Hardware connection