想用PWM 来驱动ws2812,然后试着用DMA+PWM 的方式,我看stm32有人做成功了,然后试着MM32F031这个芯片,
- #define TIM2_CCR2_Address 0x40000038
- void DMA_TIM2_Init()
- {
- NVIC_InitTypeDef NVIC_InitStructure;
- DMA_InitTypeDef DMA_InitStructure;
- DMA_DeInit(DMA1_Channel3); //通道2
- RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
-
- DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)TIM2_CCR2_Address; //目标地址
- DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)LED_BYTE_Buffer; //数据地址
- DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST; //传输方向 MtoP
- DMA_InitStructure.DMA_BufferSize = 10;
- DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; //TIM2_CCR2地址不变
- DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; // automatically increase buffer index
- DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word; //16位
- DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_HalfWord;
- DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; // stop DMA feed after buffer size is reached
- //不循环
- DMA_InitStructure.DMA_Priority = DMA_Priority_High; //通道优先级 高
- DMA_InitStructure.DMA_M2M = DMA_M2M_Disable; //非存储器到存储器
-
- NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel2_3_IRQn;
- NVIC_InitStructure.NVIC_IRQChannelPriority = 2;
- NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
- NVIC_Init(&NVIC_InitStructure);
- DMA_Init(DMA1_Channel3, &DMA_InitStructure);
- DMA_ITConfig(DMA1_Channel3, DMA_IT_TC, ENABLE);
-
- }
这是我DMA 的初始化
- void TIM2_PWM_Init(u16 arr,u16 psc,u16 pluse)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- TIM_OCInitTypeDef TIM_OCInitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //打开定时器2的时钟
- //复用初始
- GPIO_PinAFConfig(GPIOB,GPIO_PinSource3,GPIO_AF_2);
- GPIO_InitStructure.GPIO_Pin = RGB_PIN; //TIM2_CH2
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB, &GPIO_InitStructure);
- TIM_DeInit(TIM2);
- TIM_TimeBaseStructure.TIM_Period = arr-1; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 不分频
- /*****TIM_Period和TIM_Prescaler决定了周期*****=(11059200)/(arr+1)*(psc+1)*/
- TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //设置时钟分割:TDTS = Tck_tim
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式
- TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位
- TIM_ARRPreloadConfig(TIM2, ENABLE); //使能TIMx在ARR上的预装载寄存器
- TIM_OCStructInit(&TIM_OCInitStructure); //装载默认值
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //选择定时器模式:TIM脉冲宽度调制模式1
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
- TIM_OCInitStructure.TIM_Pulse = pluse; //设置待装入捕获比较寄存器的脉冲值
- /*******TIM_Pulse决定了占空比******/
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
- TIM_OC2Init(TIM2, &TIM_OCInitStructure); //根据TIM_OCInitStruct中指定的参数初始化外设TIMx
- TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable); //CH2预装载使能
- TIM_DMACmd(TIM2, TIM_DMA_Update|TIM_DMA_Trigger, ENABLE);
- TIM_DMACmd(TIM2, TIM_DMA_CC2, ENABLE);
- // TIM_Cmd(TIM2, ENABLE); //使能TIMx
- }
这是PWM 的初始化
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