CH32V003 ST7735 Driver

A minimal ST7735 LCD driver for CH32V003 that supports both ch32v003fun and PlatformIO CH32V. It should also work in MounRiver Studio.

DMA is used to accelerate the data transmission where possible.

• CH32V003 ST7735 Driver
  • Usage
    • Wiring
    • Initialization
    • Text
    • Drawing
  • Configuration
    • Change Resolution and Offset
    • RGB Color Macro
    • Set Rotation and RGB Ordering
    • Invert Colors
  • Known Issues
  • CH32V003 Development Guide
  • References
  • License

Usage

Wiring

ST7735 8-pin module

CH32V003	ST7735	Power	Description
	1 - LEDA		Connect to 3V3 via a 15-100Ω resistor
	2 - GND	GND	GND
PC2	3 - RESET		Reset
PC3	4 - RS		DC (Data / Command)
PC6 (SPI MOSI)	5 - SDA		SPI MOSI (Master Output Slave In)
PC5 (SPI SCLK)	6 - SCL		SPI SCLK (Serial Clock)
	7 - VDD	3V3	VDD
PC4	8 - CS		SPI CS/SS (Chip/Slave Select)

Note: To not use CS, define the ST7735_NO_CS macro in st7735.h. Make ST7735 always enabled by pulling CS to ground.

#define ST7735_NO_CS

Initialization

Include the header file.

#include "st7735.h"

Then invoke tft_init() function to initialize the driver.

tft_init();

Text

Print a string.

tft_set_color(RED);
tft_set_background_color(BLACK);
tft_set_cursor(2, 2);
tft_print("Hello World!");

Print integers.

tft_set_color(RED);
tft_set_background_color(BLACK);
tft_set_cursor(2, 10);
tft_print_number(123, 0);   // Align left as the width is less thant the number.
tft_set_cursor(2, 20);
tft_print_number(-123, 30); // Align right as the width is greater than the number.

Drawing

Draw a pixel.

tft_draw_pixel(80, 30, RED);

Draw a line.

tft_draw_line(10, 10, 30, 30, BLUE);

Draw a rectangle.

tft_draw_rect(10, 10, 30, 30, BLUE);

Fill a rectangle area.

tft_fill_rect(10, 10, 30, 30, BLUE);

Configuration

Depends on which ST7735 variants you have, it may require different configurations. You can configure the behavior in st7735.h or st7735.c.

Change Resolution and Offset

// st7735.h
#define ST7735_WIDTH    160
#define ST7735_HEIGHT   80
#define ST7735_X_OFFSET 1
#define ST7735_Y_OFFSET 26

RGB Color Macro

// st7735.h
#define RGB565(r, g, b) ((((r)&0xF8) << 8) | (((g)&0xFC) << 3) | ((b) >> 3))
#define BGR565(r, g, b) ((((b)&0xF8) << 8) | (((g)&0xFC) << 3) | ((r) >> 3))
#define RGB             RGB565

Set Rotation and RGB Ordering

// st7735.c
void tft_init(void)
{
    ...
    // Set rotation
    write_command_8(ST7735_MADCTL);
    write_data_8(ST7735_MADCTL_MY | ST7735_MADCTL_MV | ST7735_MADCTL_BGR);  // 0 - Horizontal
    // write_data_8(ST7735_MADCTL_BGR);                                        // 1 - Vertical
    // write_data_8(ST7735_MADCTL_MX | ST7735_MADCTL_MV | ST7735_MADCTL_BGR);  // 2 - Horizontal
    // write_data_8(ST7735_MADCTL_MX | ST7735_MADCTL_MY | ST7735_MADCTL_BGR);  // 3 - Vertical
    ...
}

Invert Colors

// st7735.c
void tft_init(void)
{
    ...
    // Invert display
    write_command_8(ST7735_INVON);
    // write_command_8(ST7735_INVOFF);
    ...
}

Known Issues

• (Fixed) The CS pin does not work understand PlatformIO. Pull the CS pin to ground as a temporary solution.
• (Fixed) The draw text function creates partial text on a diagonal line from top left, I thought it is caused by hardware, it turns out I set a mistake the Y coordinate as X coordinate.

CH32V003 Development Guide

CH32V003 Development Guide

References

• moononournation: Arduino_GFX
• Morita_Hikaru: CH32V003/Driver/CH32V003_LCD_Driver.zip
• E. Brombaugh: SPI OLED demonstration

License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA 4.0).

• Attribution - You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
• NonCommercial - You may not use the material for commercial purposes.
• ShareAlike - If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.