使用Stm32F103C8t6的定时器2通道1PWM+DMA驱动W2812B代码

以下是使用Stm32F103C8t6的定时器2通道1PWM+DMA驱动W2812B的代码，可以参考：

#include "stm32f10x.h"

#define LED_NUM 8   // 定义LED数量
#define LED_BUF_SIZE (LED_NUM * 24) // 定义LED数据缓存大小

// 定义W2812B的高电平和低电平的时间
#define T0H 14
#define T1H 52
#define TL  52

// 定义W2812B的数据格式
typedef struct {
    uint8_t g;
    uint8_t r;
    uint8_t b;
} color_t;

// 定义LED数据缓存
color_t led_buf[LED_NUM];

// 定义DMA传输完成标志位
volatile uint8_t dma_tx_complete = 0;

void delay_us(uint32_t us) {
    SysTick->LOAD = 72 * us;
    SysTick->CTRL = SysTick_CTRL_ENABLE_Msk | SysTick_CTRL_CLKSOURCE_Msk;
    while(!(SysTick->CTRL & SysTick_CTRL_COUNTFLAG_Msk));
    SysTick->CTRL = 0;
}

void init_pwm(void) {
    // 使能定时器2和GPIOA的时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    // 初始化GPIOA的PA0引脚为复用推挽输出模式
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // 初始化定时器2的PWM模式
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Period = 89;    // PWM周期为90个时钟周期
    TIM_TimeBaseStructure.TIM_Prescaler = 0;  // 不分频
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

    TIM_OCInitTypeDef TIM_OCInitStructure;
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM2, &TIM_OCInitStructure);

    // 启用定时器2的PWM输出
    TIM_Cmd(TIM2, ENABLE);
}

void init_dma(void) {
    // 使能DMA1时钟
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

    DMA_InitTypeDef DMA_InitStructure;
    DMA_DeInit(DMA1_Channel7);
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&TIM2->CCR1;  // 定时器2的通道1
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)led_buf;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
    DMA_InitStructure.DMA_BufferSize = LED_BUF_SIZE;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel7, &DMA_InitStructure);

    // 配置DMA1通道7传输完成中断
    DMA_ITConfig(DMA1_Channel7, DMA_IT_TC, ENABLE);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel7_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    // 启用DMA1通道7
    DMA_Cmd(DMA1_Channel7, ENABLE);
}

void dma_tx_complete_irqhandler(void) {
    // 清除传输完成标志位
    DMA_ClearITPendingBit(DMA1_IT_TC7);

    dma_tx_complete = 1;
}

void send_led_data(void) {
    uint16_t i, j;
    uint8_t data;

    // 填充LED数据缓存
    for(i = 0; i < LED_NUM; i++) {
        for(j = 0; j < 8; j++) {
            data = (led_buf[i].g << j) & 0x80 ? T1H : T0H;
            *(&led_buf[i].g + 1) <<= 1;
            led_buf[i].g |= data > TL;

            data = (led_buf[i].r << j) & 0x80 ? T1H : T0H;
            *(&led_buf[i].r + 1) <<= 1;
            led_buf[i].r |= data > TL;

            data = (led_buf[i].b << j) & 0x80 ? T1H : T0H;
            *(&led_buf[i].b + 1) <<= 1;
            led_buf[i].b |= data > TL;
        }
    }

    // 等待上一次传输完成
    while(!dma_tx_complete);

    // 清除传输完成标志位
    dma_tx_complete = 0;

    // 启动DMA传输
    DMA_Cmd(DMA1_Channel7, DISABLE);
    DMA_SetCurrDataCounter(DMA1_Channel7, LED_BUF_SIZE);
    DMA_Cmd(DMA1_Channel7, ENABLE);
}

int main(void) {
    // 初始化SysTick定时器，用于延时
    SysTick_Config(SystemCoreClock / 1000000);

    // 初始化PWM输出
    init_pwm();

    // 初始化DMA传输
    init_dma();

    // 填充LED数据缓存
    int i;
    for(i = 0; i < LED_NUM; i++) {
        led_buf[i].r = 0x00;
        led_buf[i].g = 0x00;
        led_buf[i].b = 0x00;
    }

    // 发送LED数据
    while(1) {
        send_led_data();
        delay_us(500);  // 500us的刷新周期
    }
}

需要注意的是，该代码在 PA0 引脚上输出 PWM 波形，因此需要将 W2812B 的 DI 引脚连接到 PA0 引脚上。另外，W2812B 的数据格式为 G-R-B（即绿色在前，红色在中间，蓝色在最后），因此在填充 LED 数据缓存时需要按照该格式填充。