ST7796S 驱动

ST7796S是一款液晶显示驱动器芯片，常用于驱动TFT LCD显示屏。它支持最大分辨率为320x480，并具有丰富的显示功能接口选项。

以下是一个使用ST7796S驱动器的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <wiringPi.h>
#include <wiringPiSPI.h>

#define ST7796S_WIDTH  320
#define ST7796S_HEIGHT 480

#define ST7796S_CMD  0x00
#define ST7796S_DATA 0x01

#define ST7796S_RST_PIN  25
#define ST7796S_DC_PIN   24
#define ST7796S_CS_PIN   8

void st7796s_write_command(uint8_t cmd) {
    digitalWrite(ST7796S_DC_PIN, ST7796S_CMD);
    wiringPiSPIDataRW(0, &cmd, 1);
}

void st7796s_write_data(uint8_t data) {
    digitalWrite(ST7796S_DC_PIN, ST7796S_DATA);
    wiringPiSPIDataRW(0, &data, 1);
}

void st7796s_init() {
    pinMode(ST7796S_RST_PIN, OUTPUT);
    pinMode(ST7796S_DC_PIN, OUTPUT);
    pinMode(ST7796S_CS_PIN, OUTPUT);

    digitalWrite(ST7796S_RST_PIN, HIGH);
    delay(10);
    digitalWrite(ST7796S_RST_PIN, LOW);
    delay(10);
    digitalWrite(ST7796S_RST_PIN, HIGH);
    delay(10);

    st7796s_write_command(0x11); // Sleep Out
    delay(120);

    st7796s_write_command(0x36); // Memory Data Access Control
    st7796s_write_data(0x48);    // BGR, MX, MY

    st7796s_write_command(0x3A); // Interface Pixel Format
    st7796s_write_data(0x55);    // 16-bit color

    st7796s_write_command(0x29); // Display On
}

void st7796s_set_pixel(uint16_t x, uint16_t y, uint16_t color) {
    st7796s_write_command(0x2A); // Column Address Set
    st7796s_write_data(x >> 8);
    st7796s_write_data(x & 0xFF);
    st7796s_write_data((x + 1) >> 8);
    st7796s_write_data((x + 1) & 0xFF);

    st7796s_write_command(0x2B); // Page Address Set
    st7796s_write_data(y >> 8);
    st7796s_write_data(y & 0xFF);
    st7796s_write_data((y + 1) >> 8);
    st7796s_write_data((y + 1) & 0xFF);

    st7796s_write_command(0x2C); // Memory Write
    st7796s_write_data(color >> 8);
    st7796s_write_data(color & 0xFF);
}

int main() {
    wiringPiSetup();
    wiringPiSPISetup(0, 8000000);

    st7796s_init();

    for (uint16_t y = 0; y < ST7796S_HEIGHT; y++) {
        for (uint16_t x = 0; x < ST7796S_WIDTH; x++) {
            uint16_t color = ((x / 10) << 11) | ((y / 10) << 5);
            st7796s_set_pixel(x, y, color);
        }
    }

    return 0;
}

这段代码使用了wiringPi库来控制树莓派的GPIO引脚和SPI接口，实现了在ST7796S驱动的TFT LCD显示屏上绘制彩色的垂直条纹。