04.WS2812B驱动实现之SPI

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04.WS2812B驱动实现之SPI [复制链接]

1、简介

前面我们介绍了通过GPIO引脚和PWM结合DMA这两种方式来实现对WS2812B的驱动，本篇帖子我们就来介绍另外一种方式：通过MCU的SPI接口来驱动WS2812B，我们通过配置SPI的8个时钟周期满足WS2812B所需要的1位所占用的时间，通过发送的数据来控制WS2812B一位当中的高低电平占比来实现；通过SPI接口，我们仅需使用到MOSI一个引脚即可，下面我们来看看程序是如何配置和实现的。

 

2、主要程序代码

#define WS2812B_SPI_BIT_H   0xF8
#define WS2812B_SPI_BIT_L   0xC0

/*******************************************************************************
 * [url=home.php?mod=space&uid=159083]@brief[/url] * @param       
 * @retval      
 * [url=home.php?mod=space&uid=1020061]@attention[/url] *******************************************************************************/
static void WS2812B_Write24Bits(uint8_t R, uint8_t G, uint8_t B)
{
    for(uint8_t i = 0; i < 8; i++)
    {
        if((G << i) & 0x80)
        {
            RGB_BitBuffer[i + 0x00] = WS2812B_SPI_BIT_H;
        }
        else
        {
            RGB_BitBuffer[i + 0x00] = WS2812B_SPI_BIT_L;
        }
    }

    for(uint8_t i = 0; i < 8; i++)
    {
        if((R << i) & 0x80)
        {
            RGB_BitBuffer[i + 0x08] = WS2812B_SPI_BIT_H;
        }
        else
        {
            RGB_BitBuffer[i + 0x08] = WS2812B_SPI_BIT_L;
        }
    }

    for(uint8_t i = 0; i < 8; i++)
    {
        if((B << i) & 0x80)
        {
            RGB_BitBuffer[i + 0x10] = WS2812B_SPI_BIT_H;
        }
        else
        {
            RGB_BitBuffer[i + 0x10] = WS2812B_SPI_BIT_L;
        }
    }

    __disable_irq();

    for(uint8_t i = 0; i < 24; i++)
    {
        while(!(SPI_STAT(SPI1) & SPI_FLAG_TBE));
        SPI_DATA(SPI1)    =    RGB_BitBuffer[i];
    }

    __enable_irq();
}

……

/*******************************************************************************
 * @brief       
 * @param       
 * @retval      
 * @attention   
*******************************************************************************/
static void WS2812B_DisplayFullColor(void)
{
    static uint8_t Index = 0;
    static uint8_t Count = 0, Mode = 0;

    uint8_t R_TAB[65] =
    {
        255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 240, 220, 
        200, 180, 160, 140, 120, 100,  80,  60,  40,  20,   0,   0,   0,   0,   0,
          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
          0,   0,   0,   0,   0,   0,   0,   0,  20,  40,  60,  80, 100, 120, 140,
        160, 180, 200, 220, 240
    };

    uint8_t G_TAB[65] =
    {
          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
          0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  20,  40,  60,
         80, 100, 120, 140, 160, 180, 200, 220, 240, 255, 255, 255, 255, 255, 255,
        255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
        255, 255, 255, 255, 255
    };

    uint8_t B_TAB[65] =
    {
          0,  20,  40,  60,  80, 100, 120, 140, 160, 180, 200, 220, 240, 255, 255,
        255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
        255, 255, 255, 255, 255, 255, 255, 255, 255, 240, 220, 200, 180, 160, 140,
        120, 100,  80,  60,  40,  20,   0,   0,   0,   0,   0,   0,   0,   0,   0,
          0,   0,   0,   0,   0
    };

    uint8_t Step = 31, CountCOMP = 30;

    switch(Mode)
    {
        case 0: RGB_Gradient(0x00,0x00,0x00, 0x00,0x00,0xFF, Step); break;
        case 1: RGB_Gradient(0x00,0x00,0x00, 0x00,0xFF,0x00, Step); break;
        case 2: RGB_Gradient(0x00,0x00,0x00, 0xFF,0x00,0x00, Step); break;
        default: break;
    }

    for(uint8_t i = 0; i < 60; i++)
    {
        if(Mode != 3)
        {
            WS2812B_Write24Bits(RGB_TAB[Index][0], RGB_TAB[Index][1], RGB_TAB[Index][2]);

            Index = (Index + 1) % Step;     CountCOMP = 30;
        }
        else
        {
            WS2812B_Write24Bits(R_TAB[Index], G_TAB[Index], B_TAB[Index]);

            Index = (Index + 1) % 65;       CountCOMP = 60;
        }
    }

    if(Count++ == CountCOMP)
    {
        Count = 0;
        Index = 0;

        Mode = (Mode + 1) % 4;
    }
}

……

/*******************************************************************************
 * @brief       
 * @param       
 * @retval      
 * @attention   
*******************************************************************************/
void WS2812B_Init(void)
{
    spi_parameter_struct spi_init_struct;

    rcu_periph_clock_enable(RCU_GPIOB);
    gpio_mode_set(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);
    gpio_af_set(GPIOB, GPIO_AF_6, GPIO_PIN_13 | GPIO_PIN_14 | GPIO_PIN_15);

    rcu_periph_clock_enable(RCU_SPI1);

    spi_i2s_deinit(SPI1);
    spi_struct_para_init(&spi_init_struct);

    spi_init_struct.trans_mode           = SPI_TRANSMODE_FULLDUPLEX;
    spi_init_struct.device_mode          = SPI_MASTER;
    spi_init_struct.frame_size           = SPI_FRAMESIZE_8BIT;
    spi_init_struct.clock_polarity_phase = SPI_CK_PL_HIGH_PH_2EDGE;
    spi_init_struct.nss                  = SPI_NSS_SOFT;
    spi_init_struct.prescale             = SPI_PSC_4;
    spi_init_struct.endian               = SPI_ENDIAN_MSB;
    spi_init(SPI1, &spi_init_struct);

    spi_fifo_access_size_config(SPI1, SPI_BYTE_ACCESS);

    spi_enable(SPI1);

    WS2812B_DisplayAllRed();    SysTick_DelayMS(500);
    WS2812B_DisplayAllGreen();  SysTick_DelayMS(500);
    WS2812B_DisplayAllBlue();   SysTick_DelayMS(500);

    TASK_Append(TASK_ID_WS2812B, WS2812B_DisplayFullColor, 50);
}

……

 

3、运行视频效果

 

 

4、时序控制截图：完美的波形

 

5、工程源码

Template_SPI.zip (391.89 KB, 下载次数: 149)

2021-12-15 21:03 上传

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freebsder

很详细，谢谢分享

wangerxian

这个效果好啊，估计幕布后面用的应该就是这种灯带！

fanwei326

这个效果很不错，代码很详细,学习了，谢谢分享！

陈哆啦

sdafegg fea

12345fish

good