STM32单片机的DAC不支持直接生成正弦波,需要用读表法生成正弦波,外加DMA传输,生成正弦波。代码如下:
完整工程在附件。
单片机源程序如下:
- #include "sign.h"
- u16 SineWave1_Value[256];
- u16 SineWave2_Value[256];
- /********正弦波输出表***********/
- //cycle :波形表的位数 (0~256)
- //Um :输出电压的峰值(0~1.5)
- /*******************************/
- void SineWave1_Data( u16 cycle ,u16 *D,float Um)
- {
- u16 i;
- for( i=0;i<cycle;i++)
- {
- D[i]=(u16)((Um*sin(( 1.0*i/(cycle-1))*2*PI)+Um)*4095/3.3);
- }
- }
- void SineWave2_Data( u16 cycle ,u16 *D,float Um)
- {
- u16 i;
- for( i=0;i<cycle;i++)
- {
- D[i]=(u16)((Um*sin(( 1.0*i/(cycle-1))*2*PI)+Um)*4095/3.3);
- }
- }
- /****************初始化引脚******************/
- void SineWave_GPIO_Config(void)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //开时钟
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; //推挽输出模式
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //输出速率
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4|GPIO_Pin_5 ; //选择引脚
- GPIO_SetBits(GPIOA,GPIO_Pin_4) ; //拉高输出
- GPIO_SetBits(GPIOA,GPIO_Pin_5) ; //拉高输出
- GPIO_Init(GPIOA, &GPIO_InitStructure); //初始化
- }
- /******************DAC初始化ˉ*************************/
- void SineWave_DAC_Config( void)
- {
- DAC_InitTypeDef DAC_InitStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);//初始化DAC的时钟
- DAC_StructInit(&DAC_InitStructure);
- DAC_InitStructure.DAC_Trigger = DAC_Trigger_T2_TRGO;//指定DAC1的触发定时器TIM2
- DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;//无波形产生
- DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable; //不是能DAC输出缓冲
- DAC_Init(DAC_Channel_1, &DAC_InitStructure);//初始化DAC channel1
- DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;//指定DAC2的触发定时器TIM6
- DAC_Init(DAC_Channel_2, &DAC_InitStructure);//初始化DAC channel2
- DAC_Cmd(DAC_Channel_1, ENABLE); //使能DAC channel1
- DAC_Cmd(DAC_Channel_2, ENABLE); //使能DAC channel2
- DAC_DMACmd(DAC_Channel_1, ENABLE); //使能DAC Channel1的DMA
- DAC_DMACmd(DAC_Channel_2, ENABLE); //使能DAC Channel2的DMA
-
- }
- /*********定时器初始化************/
- void SineWave_TIM_Config(u32 Wave1_Fre,u32 Wave2_Fre)
- {
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2|RCC_APB1Periph_TIM6, ENABLE);//开时钟
- TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
- TIM_TimeBaseStructure.TIM_Period = Wave1_Fre; //正弦波1频率设置
- TIM_TimeBaseStructure.TIM_Prescaler = 0x0; //没有预分频
- TIM_TimeBaseStructure.TIM_ClockDivision = 0x0; //时钟不分频
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//增计数
- TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
- TIM_TimeBaseStructure.TIM_Period = Wave2_Fre; //正弦波2频率设置
- TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);
- TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);//更新TIM2输出触发
- TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_Update);//更新TIM6输出触发
- }
- /*********DMA配置***********/
- void SineWave_DMA_Config(void)
- {
- DMA_InitTypeDef DMA_InitStructure;
- RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);//初始化DMA2的时钟
- DMA_DeInit(DMA2_Channel3); //将DMA配置成默认值
- DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR12R1;//指定DMA2通道3的目标地址为DAC1_DHR12R1
- DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)SineWave1_Value;//指定DMA的源地址为数组Sine12bit
- DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;//外设作为数据传输的目的地
- DMA_InitStructure.DMA_BufferSize = 256;//DMA缓冲区大小
- DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设机地址存器不变
- DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址寄存器递增
- DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;//外设数据宽度为半字
- DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;//内存数据宽度为半字
- DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;//工作在循环缓存模式,数据传输数为0时,自动恢复配置初值
- DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;//非常高优先级
- DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//通道未被设置成内存到内存模式,与循环模式相对
- DMA_Init(DMA2_Channel3, &DMA_InitStructure);//初始化DMA
- DMA_DeInit(DMA2_Channel4);
- DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR12R2;//指定DMA2通道3的目标地址为DAC2_DHR12R2
- DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)SineWave2_Value;//指定DMA的源地址为数组Sine12bit
- DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;//外设作为数据传输的目的地
- DMA_InitStructure.DMA_BufferSize = 256;//DMA缓冲区大小
- DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设机地址存器不变
- DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //内存地址寄存器递增
- DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;//外设数据宽度为半字
- DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;//内存数据宽度为半字
- DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;//工作在循环缓存模式,数据传输数为0时,自动恢复配置初值
- DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//通道未被设置成? 诖娴侥诖婺J剑胙纺J较喽?
- DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
- DMA_Init(DMA2_Channel4, &DMA_InitStructure);
- DMA_Cmd(DMA2_Channel3, ENABLE); //使能DMA的channel3
- DMA_Cmd(DMA2_Channel4, ENABLE); //使能DMA的channel4
-
-
- }
- /**********正弦波初始化**********************/
- //Wave1_Fre: 频率值(0~60 000)Hz
- //Um : 电压峰值(0.0~1.5)V
- /*******************************************/
- void SineWave_Init(u16 Wave1_Fre,u16 Wave2_Fre,float Um)
- {
- u32 f1,f2;
- f1=(u32)(72000000/sizeof(SineWave1_Value)*2/Wave1_Fre);//计算频率
- f2=(u32)(72000000/sizeof(SineWave2_Value)*2/Wave2_Fre);//计算频率
- SineWave1_Data(256,SineWave1_Value,Um); //生成输出正弦波的波形表
- SineWave1_Data(256,SineWave2_Value,Um); //生成输出正弦波的波形表
- SineWave_GPIO_Config(); //初始化io
- SineWave_TIM_Config(f1,f2); //初始化定时器2
- SineWave_DAC_Config(); //配置DAC
- SineWave_DMA_Config(); //配置DMA
- TIM_Cmd(TIM2, ENABLE); //开启定时器
- TIM_Cmd(TIM6, ENABLE); //开启定时器
- }
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