【APM32F411V Tiny开发板测评】2、3线SPI+DMA驱动HX8347屏

sujingliang

手头有一种HX8347主控的屏幕，有RGB和3线SPI接口，这块屏原本的设计是SPI是配置接口，RGB接口是MCU驱动接口。但是RGB接线太多，用起来还是比较复杂。SPI接口尽管是配置接口，也可以用来驱动屏幕。不过是3线SPI，缺少DC引脚，DC需要用发送数据的方式解决。

根据HX8347的手册

就是在发送数据前，需要先发送一个字节，如发送0×70，表示后面跟的是指令；发送0×72，表示后面跟的是数据。

一、SPI配置

apm32f4xx_spi_cfg.c

void DAL_SPI_Config(void)
{
    /* Configures SPI1 */
    hspi1.Instance                  = SPI1;
    hspi1.Init.Mode                 = SPI_MODE_MASTER;
    hspi1.Init.Direction            = SPI_DIRECTION_2LINES;
    hspi1.Init.DataSize             = SPI_DATASIZE_8BIT;
    hspi1.Init.CLKPolarity          = SPI_POLARITY_LOW;
    hspi1.Init.CLKPhase             = SPI_PHASE_1EDGE;
    hspi1.Init.NSS                  = SPI_NSS_SOFT;
    hspi1.Init.BaudRatePrescaler    = SPI_BAUDRATEPRESCALER_4;
    hspi1.Init.FirstBit             = SPI_FIRSTBIT_MSB;
    hspi1.Init.TIMode               = SPI_TIMODE_DISABLE;
    hspi1.Init.CRCCalculation       = SPI_CRCCALCULATION_DISABLE;
    hspi1.Init.CRCPolynomial        = 7U;
    if (DAL_SPI_Init(&hspi1) != DAL_OK)
    {
        DAL_ErrorHandler();
    }
}

SPI1设置为SPI主设备，波特率最高只能设到SPI_BAUDRATEPRESCALER_4

void DAL_SPI_MspInit(SPI_HandleTypeDef *hspi)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0U};

    if(hspi->Instance == SPI1)
    {
        /* Enable peripheral clock */
        __DAL_RCM_SPI1_CLK_ENABLE();

        /* Enable peripheral GPIO clock */
        __DAL_RCM_GPIOA_CLK_ENABLE();

        /* Configure the SPI pin */
        GPIO_InitStruct.Pin         = GPIO_PIN_5 | GPIO_PIN_7;
        GPIO_InitStruct.Mode        = GPIO_MODE_AF_PP;
        GPIO_InitStruct.Pull        = GPIO_PULLUP;
        GPIO_InitStruct.Speed       = GPIO_SPEED_FREQ_MEDIUM;
        GPIO_InitStruct.Alternate   = GPIO_AF5_SPI1;
        DAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
		
    }	
		
   /* DMA Init */
    hdma2.Instance = DMA2_Stream2;
    hdma2.Init.Channel              = DMA_CHANNEL_2;
    hdma2.Init.Direction            = DMA_MEMORY_TO_PERIPH;
    hdma2.Init.PeriphInc            = DMA_PINC_DISABLE;
    hdma2.Init.MemInc               = DMA_MINC_ENABLE;
    hdma2.Init.PeriphDataAlignment  = DMA_PDATAALIGN_BYTE;
    hdma2.Init.MemDataAlignment     = DMA_MDATAALIGN_BYTE;
    hdma2.Init.Mode                 = DMA_NORMAL;
    hdma2.Init.Priority             = DMA_PRIORITY_LOW;
    hdma2.Init.FIFOMode             = DMA_FIFOMODE_DISABLE;
		//hdma2.XferCpltCallback					=	DMA_Callbackup;
    if (DAL_DMA_Init(&hdma2) != DAL_OK)
    {
        DAL_ErrorHandler();
    }
  //用于在 HAL 库的数据结构之间建立链接
  __DAL_LINKDMA(&hspi1,hdmatx,hdma2);
		

  /* SPI1 interrupt Init */
  DAL_NVIC_SetPriority(SPI1_IRQn, 0, 0);
  DAL_NVIC_EnableIRQ(SPI1_IRQn);
}

DAL_SPI_MspInit中需要设置复用引脚，只设置了SCL和SDA(MOSI)，CS需要自己控制。试了好久，引脚的速率最高只能GPIO_SPEED_FREQ_MEDIUM。
另外DMA也需要在这里设置。中断设置不是必须。

二、DMA配置

apm32f4xx_dma_cfg.c

void DAL_DMA_Config(void)
{
    __DAL_RCM_DMA2_CLK_ENABLE();
       DAL_NVIC_SetPriority(DMA2_Stream2_IRQn, 0, 0);
       DAL_NVIC_EnableIRQ(DMA2_Stream2_IRQn);
 }

只有时钟和中断。其他在apm32f4xx_spi_cfg.c中配置。

三、HX8347配置
1、配置CS、RST、背光引脚

void LCD_GPIO_Init(void)
{
   GPIO_InitTypeDef GPIO_InitStructure = {0};
 __DAL_RCM_GPIOA_CLK_ENABLE();
   GPIO_InitStructure.Pin = LCD_CS|LCD_RST|LCD_LED;
   GPIO_InitStructure.Mode = GPIO_MODE_OUTPUT_PP;
   GPIO_InitStructure.Speed = GPIO_SPEED_FAST;
   DAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
}

2、向SPI总线写一个BYTE

void  SPI_WriteData(unsigned char Data)
{
	DAL_SPI_Transmit_DMA(&hspi1,&Data,1);
        while(DAL_DMA_GetState(&hdma2)==DAL_DMA_STATE_BUSY);
}

3、写指令

void Lcd_WriteIndex(unsigned char Index)
{
   LCD_CS_CLR;
   SPI_WriteData(0x70);
   SPI_WriteData(Index);
   LCD_CS_SET;
}

4、写数据

void Lcd_WriteData(unsigned char Data)
{
   LCD_CS_CLR;

   SPI_WriteData(0x72);
   SPI_WriteData(Data);

   LCD_CS_SET;
}

5、写寄存器

void Lcd_Write_REG(unsigned char Index,unsigned char Data)
{
    Lcd_WriteIndex(Index);
    Lcd_WriteData(Data);
}

6、设置画图输出范围

void LCD_SetWindow(unsigned int x1,unsigned int y1,unsigned int x2,unsigned int y2)
{

    //SC
    Lcd_Write_REG(0x02,x1>>8);       // Column address start2
    Lcd_Write_REG(0x03,(uint8_t)x1);          // Column address start1
    //EC
    Lcd_Write_REG(0x04,x2>>8);       // Column address end2
    Lcd_Write_REG(0x05,(uint8_t)x2);          // Column address end1
    //SP
    Lcd_Write_REG(0x06,y1>>8);       // Row address start2
    Lcd_Write_REG(0x07,(uint8_t)y1);          // Row address start1
    //EP
    Lcd_Write_REG(0x08,y2>>8);       // Row address end2
    Lcd_Write_REG(0x09,(uint8_t)y2);          // Row address end1
    //写0x22到index register，那么下次send data就会直接被写到graphic ram
    Lcd_WriteIndex(0x22);
}

7、DMA方式清屏

void FillRect_DMA(uint16_t color)
{
    int16_t j;
    LCD_SetWindow(0, 0,239,319);

    LCD_CS_CLR;
    SPI_WriteData(0x72);

    for(j=0 ;j<Buf_Size;j+=2){
        TxData[j] = color>>8;
        TxData[j+1] = color;
    }

    for(j = 0 ; j<320/(Buf_Size/480) ; j++){
			DAL_SPI_Transmit_DMA(&hspi1,TxData,Buf_Size);
			while(DAL_DMA_GetState(&hdma2)==DAL_DMA_STATE_BUSY);
    }
    LCD_CS_SET;
}

8、写汉字及ASCII

void Gui_DrawFont_GBK16_DMA(unsigned int x, unsigned int y, unsigned int fc, unsigned int bc,unsigned char *s)
{
    unsigned char i,j;
    unsigned short k,x0,y0;
    x0=x;
    y0=y;
    x=0;
    y=0;

    DMA_BUFFER_RESET(bc);       //清缓存
    while(*s)
    {

        if((*s) < 128)
        {
            k=*s;
            if (k==13)
            {
                x=x0;
                y+=16;
            }
            else
            {
                if (k>32) k-=32; else k=0;

                for(i=0;i<16;i++)
                for(j=0;j<8;j++)
                    {
                        if(asc16[k*16+i]&(0x80>>j)) Gui_DrawPoint_DMA(x+j,y+i,fc);
                        else
                        {
                            if (fc!=bc) Gui_DrawPoint_DMA(x+j,y+i,bc);
                        }
                    }
                x+=8;
            }
            s++;
        }

        else
        {


            for (k=0;k<hz16_num;k++)
            {
              if ((hz16[k].Index[0]==*(s))&&(hz16[k].Index[1]==*(s+1)))
              {

                    for(i=0;i<16;i++)
                    {
                        for(j=0;j<8;j++)
                            {
                                if(hz16[k].Msk[i*2]&(0x80>>j))  Gui_DrawPoint_DMA(x+j,y+i,fc);
                                else {
                                    if (fc!=bc) Gui_DrawPoint_DMA(x+j,y+i,bc);
                                }
                            }
                        for(j=0;j<8;j++)
                            {
                                if(hz16[k].Msk[i*2+1]&(0x80>>j))   Gui_DrawPoint_DMA(x+j+8,y+i,fc);
                                else
                                {
                                    if (fc!=bc) Gui_DrawPoint_DMA(x+j+8,y+i,bc);
                                }
                            }
                    }
                }
              }
            s+=2;x+=16;
        }

    }

    LCD_SetWindow(0,y0,239,y0+16);
    LCD_CS_CLR;
    SPI_WriteData(0x72);


    DAL_SPI_Transmit_DMA(&hspi1,TxData,Buf_Size);
		while(DAL_DMA_GetState(&hdma2)==DAL_DMA_STATE_BUSY);
				
    LCD_CS_SET;

}

四、效果

五、总结

1、SPI+DMA网上其实已经写了很多，但通常是基于标准库的，基于HAL(DAL)库还是比较少。
2、这个屏比较特殊3线SPI，需要稍微特殊处理下。
3、SPI的设置速率不是越快越好，太快HX8347跟不上，需要找到一个平衡点，尽可能提高速度。