【XR806开发板试用】移植st7789屏幕驱动

SDK下载和环境搭建

如果提示 Username for : 请输入 全志在线开发者论坛 的用户名和密码。（注：需要全志在线开发者论坛LV2等级以上用户才有权限拉取 SDK，随便注册个账户，灌灌水就到了）

由于 SDK 普遍较大，拉取可能需要一定的时间。

接下来安装环境依赖（我用Buildroot的docker容器，都装过了，就不需要再搞了）

sudo apt-get install build-essential subversion git libncurses5-dev zlib1g-dev gawk flex bison quilt libssl-dev xsltproc libxml-parser-perl mercurial bzr ecj cvs unzip lsof kconfig-frontends android-tools-mkbootimg python2 libpython3-dev gcc-multilib libc6:i386 libstdc++6:i386 lib32z1

然后配置工具链，直接下载gcc-arm-none-eabi-8-2019-q3-update-linux.tar.bz2 压缩包并解压缩到~/.bin目录下，并修改gcc.mk文件

# ----------------------------------------------------------------------------
# cross compiler
# ----------------------------------------------------------------------------
CC_DIR := /home/vuser/.bin/gcc-arm-8.3/bin/
CC_PREFIX := ccache $(CC_DIR)/arm-none-eabi-

这样就配置好了。看了一下project/example目录下，有个spi工程，适合拿来修改，就是它了。

移植st7789驱动

ST7789是一款高度集成的彩色TFT液晶显示屏控制器芯片，通常用于驱动小到中等尺寸的液晶屏。例如淘宝上常见的1.4寸、1.47寸、1.69寸屏幕等等。
现在就开始吧，首先新建st7789.c和st7789.h文件。然后创建用于初始化st7789芯片的命令序列表。

static lcd_init_cmd_t st7789_init_cmds[] = {
    {0x01, {0}, 0x80, 120},
    /* Sleep Out */
    {0x11, {0}, 0x80, 120},
    /* Memory Data Access Control, MX=MV=1, MY=ML=MH=0, RGB=0 */
    {0x36, {0x00}, 1},
    /* Interface Pixel Format, 16bits/pixel for RGB/MCU interface */
    {0x3A, {0x05}, 1},
#if 0
      {0x30, {0x00,0x50,0x01,0x3F}, 4},
      {0x12, {0x00}, 0},
#endif
    /* Porch Setting */
    {0xB2, {0x0c, 0x0c, 0x00, 0x33, 0x33}, 5},
    /* Gate Control, Vgh=13.65V, Vgl=-10.43V */
    {0xB7, {0x35}, 1},
    /* VCOM Setting, VCOM=1.35V */
    {0xBB, {0x32}, 1},
    // /* LCM Control, XOR: BGR, MX, MH */
    // {0xC0, {0x2C}, 1},
    /* VDV and VRH Command Enable, enable=1 */
    {0xC2, {0x01, 0xFF}, 2},
    /* VRH Set, Vap=4.4+... */
    {0xC3, {0x15}, 1},
    /* VDV Set, VDV=0 */
    {0xC4, {0x20}, 1},
    /* Frame Rate Control, 60Hz, inversion=0 */
    {0xC6, {0x0F}, 1},
    /* Power Control 1, AVDD=6.8V, AVCL=-4.8V, VDDS=2.3V */
    {0xD0, {0xA4, 0xA1}, 1},
    /* Positive Voltage Gamma Control */
    {0xE0,
     {0xD0, 0x08, 0x0E, 0x09, 0x09, 0x05, 0x31, 0x33, 0x48, 0x17, 0x14, 0x15,
      0x31, 0x34},
     14},
    /* Negative Voltage Gamma Control */
    {0xE1,
     {0xD0, 0x08, 0x0E, 0x09, 0x09, 0x15, 0x31, 0x33, 0x48, 0x17, 0x14, 0x15,
      0x31, 0x34},
     14},
    /* Display On */
    {0x21, {0}, 0},
    {0x29, {0}, 0},
    {0, {0}, 0xff}};

这个序列表使用的是这样的数据结构

/*The LCD needs a bunch of command/argument values to be initialized. They are
 * stored in this struct. */
typedef struct {
  # 指令
  uint8_t cmd;
  # 数据
  uint8_t data[16];
  # 数据长度和类型，一般初始化数据不会很长，使用部分做其他用。
  # 例如 0x80代表需要延时，延时时间由delaytime指定，0xFF代表结束
  uint8_t databytes; // No of data in data; bit 7 = delay after set; 0xFF =
                     // end of cmds.
  uint8_t delaytime; // delaytime
} lcd_init_cmd_t;

然后编写初始化函数，这里把gpio和spi的初始化都放在里面了。

printf("ST7789 initialization.n");

  int ret = dirver_spi_init();
  if (ret != 0) {
    printf("SPI dev init fail!n");
  }

  gpio_init(disp_pin_dc);
  gpio_init(disp_pin_rst);
  gpio_init(disp_pin_bckl);

  HAL_SPI_CS(DEMO_SPI_PORT, 1);
  // Reset the displayc
  gpio_set_level(disp_pin_rst, 1);
  OS_MSleep(1);
  gpio_set_level(disp_pin_rst, 0);
  OS_MSleep(100);
  gpio_set_level(disp_pin_rst, 1);
  OS_MSleep(100);

  st7789_enable_backlight(true);
  OS_MSleep(100);

  // Send all the commands
  uint16_t cmd = 0;
  while (st7789_init_cmds[cmd].databytes != 0xff) {
    printf("Send command 0x%02xn", st7789_init_cmds[cmd].cmd);
    st7789_send_cmd(st7789_init_cmds[cmd].cmd);
    if ((st7789_init_cmds[cmd].databytes & 0x1F) != 0) {
      st7789_send_data(st7789_init_cmds[cmd].data,
                       st7789_init_cmds[cmd].databytes & 0x1F);
    }
    if (st7789_init_cmds[cmd].databytes & 0x80) {
      OS_MSleep(st7789_init_cmds[cmd].delaytime);
    }
    cmd++;
  }
  printf("init finish.n");
  st7789_set_orientation(DISPLAY_ORIENTATION);

硬件连接如图所示

为什么RES引脚直接接的VCC，因为不知道是这个芯片的问题还是什么问题。RES引脚接到推挽输出的IO引脚后，屏幕也能点亮，但是亮度莫名其妙很低。手上几个屏都测试了一下，都这样。

然后就是编写一下写命令和写数据的函数，写命令时需要设置一下DC引脚，然后写完立即将DC引脚切换回高电平。

static void st7789_send_cmd(uint8_t cmd) {
  gpio_set_level(disp_pin_dc, 0);
  dirver_spi_send_data(&cmd, 1);
  gpio_set_level(disp_pin_dc, 1);
}
static void st7789_send_data(void *data, uint16_t length) {
  dirver_spi_send_data(data, length);
}

然后就是编写屏幕翻转配置函数

static void st7789_set_orientation(uint8_t orientation) {
  // ESP_ASSERT(orientation < 4);

  const char *orientation_str[] = {"PORTRAIT", "PORTRAIT_INVERTED", "LANDSCAPE",
                                   "LANDSCAPE_INVERTED"};

  printf("Display orientation: %sn", orientation_str[orientation]);

  uint8_t data[] = {0xC0, 0x00, 0x60, 0xA0};

  printf("0x36 command value: 0x%02Xn", data[orientation]);

  st7789_send_cmd(ST7789_MADCTL);
  st7789_send_data((void *)&data[orientation], 1);
}

最后再写一下写屏函数即可，这里为了快速刷屏，设置了比较大的缓存区。目前还不会使用XR806的DMA，学会了可以减少缓存RAM的大小。

/* The ST7789 display controller can drive 320*240 displays, when using a
 * 240*240 display there's a gap of 80px, we need to edit the coordinates to
 * take into account that gap, this is not necessary in all orientations. */
void st7789_flush(uint16_t x1, uint16_t x2, uint16_t y1, uint16_t y2,
                  uint16_t color) {
  uint8_t data[4] = {0};

  uint16_t offsetx1 = x1;
  uint16_t offsetx2 = x2;
  uint16_t offsety1 = y1;
  uint16_t offsety2 = y2;

#if (TFT_DISPLAY_OFFSETS)
  offsetx1 += TFT_DISPLAY_X_OFFSET;
  offsetx2 += TFT_DISPLAY_X_OFFSET;
  offsety1 += TFT_DISPLAY_Y_OFFSET;
  offsety2 += TFT_DISPLAY_Y_OFFSET;

#elif (LV_HOR_RES_MAX == 320) && (LV_VER_RES_MAX == 320)
#if (DISPLAY_ORIENTATION_PORTRAIT)
  offsetx1 += 80;
  offsetx2 += 80;
#elif (DISPLAY_ORIENTATION_LANDSCAPE_INVERTED)
  offsety1 += 80;
  offsety2 += 80;
#endif
#endif

  /*Column addresses*/
  st7789_send_cmd(ST7789_CASET);
  data[0] = (offsetx1 > > 8) & 0xFF;
  data[1] = offsetx1 & 0xFF;
  data[2] = (offsetx2 > > 8) & 0xFF;
  data[3] = offsetx2 & 0xFF;
  st7789_send_data(data, 4);

  /*Page addresses*/
  st7789_send_cmd(ST7789_RASET);
  data[0] = (offsety1 > > 8) & 0xFF;
  data[1] = offsety1 & 0xFF;
  data[2] = (offsety2 > > 8) & 0xFF;
  data[3] = offsety2 & 0xFF;
  st7789_send_data(data, 4);

  /*Display On*/
  st7789_send_cmd(ST7789_DISPON);
  /*Memory write*/
  st7789_send_cmd(ST7789_RAMWR);

  uint32_t size = (y2 - y1) * (x2 - x1);

  uint32_t buffsize = (x2 - x1) * 80;
  unsigned char *burst_buffer = (unsigned char *)malloc(buffsize * 2);

  for (uint32_t i = 0; i < size + buffsize; i += buffsize) {
    for (uint32_t j = 0; j < buffsize; j++) {
      burst_buffer[2 * j] = color > > 8;
      burst_buffer[2 * j + 1] = color;
    }
    st7789_send_data(burst_buffer, buffsize * 2);
  }

  free(burst_buffer);
}

还需要添加一个刷屏函数作为测试，现在补一下。
由于1.69寸屏幕不需要设置屏幕窗口偏移量，就直接按满屏来刷了。

void lcd_clear(uint16_t color) { st7789_flush(0, 240, 0, 320, color); }

然后在main.c里调用屏幕初始化和刷屏函数就可以啦。

#include "common/framework/platform_init.h"
#include "kernel/os/os.h"
#include < stdio.h >

extern void st7789_init();
extern void st7789_flush(uint16_t x1, uint16_t x2, uint16_t y1, uint16_t y2,
                         uint16_t color);
extern void lcd_clear(uint16_t color);

int main(void) {

  platform_init();

  printf("gpio demo started.n");

  st7789_init();
  printf("flush color.n");
  // st7789_flush(0, 240, 0, 280, 0xFFFF);

  while (1) {
    lcd_clear(0x0000);
    OS_MSleep(1000);
    lcd_clear(0xFFFF);
    OS_MSleep(1000);
    lcd_clear(0xEF5D);
    OS_MSleep(1000);
    lcd_clear(0xF800);
    OS_MSleep(1000);
    lcd_clear(0x07E0);
    OS_MSleep(1000);
    lcd_clear(0x001F);
    OS_MSleep(1000);
  }

  printf("never run here.n");
  return 0;
}

# 清除错误用
void main_cmd_exec(char *cmd) {}

刷屏效果如图

经过测试，手上的1.47寸屏幕和1.69寸st7789屏幕都可以正常驱动。