问题描述:我用
STM32f207的PA4(DAC通道1)、PA5(DAC通道2)输出正玄波和余弦波,利用了DMA和
tiM2和TIM6分别做触发,TIM2触发DMA1_Stream5,TIM6触发DMA1_Stream6,PA4输出了正弦波,PA5输出了余弦波, TIM2->ARR = 20; TIM6->ARR = 20;输出频率相同,看不出问题,可是问题出在哪里呢?问题在于,当ARR的值小于15的时候,比如 TIM2->ARR = 14;
TIM6->ARR = 14;
问题来了,通道1一直是高电平,通道输出余弦波正常。
于是改变用TIM2触发DMA1_Stream6,TIM6触发DMA1_Stream5,ARR都为14(低于15都一样); 同样还是通道一有同样的问题,二通道2却正常输出了波形。于是我想跟TIM没有关系,后来也尝试改变波形数据,发现也不是波形数据的问题。不知道是否有大神帮我分析一下这个问题是怎么回事。我用的是keil工具。数据是用EXCEl计算出来的,应该是没有问题的。代码如下:
#include "stm32f2xx_dac.h"
#include "stm32f2xx_dma.h"
#include "stm32f2xx.h"
#define DAC1_DMA_ADDR 0x40007408 // DAC通道1地址
#define DAC2_DMA_ADDR 0x40007414 // DAC通道2地址
uc32 DAC_sinTAB[]={
2000 ,2098 ,2196 ,2293 ,2390 ,2486 ,2581 ,2674 ,
2765 ,2855 ,2943 ,3028 ,3111 ,3191 ,3269 ,3343 ,
3414 ,3482 ,3546 ,3606 ,3663 ,3715 ,3764 ,3808 ,
3848 ,3883 ,3914 ,3940 ,3962 ,3978 ,3990 ,3998 ,
4000 ,3998 ,3990 ,3978 ,3962 ,3940 ,3914 ,3883 ,
3848 ,3808 ,3764 ,3715 ,3663 ,3606 ,3546 ,3482 ,
3414 ,3343 ,3269 ,3191 ,3111 ,3028 ,2943 ,2855 ,
2765 ,2674 ,2581 ,2486 ,2390 ,2293 ,2196 ,2098 ,
2000 ,1902 ,1804 ,1707 ,1610 ,1514 ,1419 ,1326 ,
1235 ,1145 ,1057 ,972 ,889 ,809 ,731 ,657 ,
586 ,518 ,454 ,394 ,337 ,285 ,236 ,192 ,
152 ,117 , 86 , 60 , 38 , 22 , 10 , 2 ,
0 , 2 , 10 , 22 , 38 , 60 , 86 ,117 ,
152 ,192 ,236 ,285 ,337 ,394 ,454 ,518 ,
586 ,657 ,731 ,809 ,889 ,972 ,1057 ,1145 ,
1235 ,1326 ,1419 ,1514 ,1610 ,1707 ,1804 ,1902
};
uc32 DAC_cosTAB[] = {
4000 ,3998 ,3990 ,3978 ,3962 ,3940 ,3914 ,3883 ,
3848 ,3808 ,3764 ,3715 ,3663 ,3606 ,3546 ,3482 ,
3414 ,3343 ,3269 ,3191 ,3111 ,3028 ,2943 ,2855 ,
2765 ,2674 ,2581 ,2486 ,2390 ,2293 ,2196 ,2098 ,
2000 ,1902 ,1804 ,1707 ,1610 ,1514 ,1419 ,1326 ,
1235 ,1145 ,1057 ,972 ,889 , 809 ,731 ,657 ,
586 ,518 ,454 ,394 ,337 ,285 , 236 ,192 ,
152 ,117 , 86 , 60 , 38 , 22 , 10 ,2 ,
0 , 2 , 10 , 22 , 38 , 60 , 86 ,117 ,
152 ,192 ,236 ,285 ,337 ,394 ,454 ,518 ,
586 ,657 ,731 ,809 ,889 ,972 ,1057 ,1145 ,
1235 ,1326 ,1419 ,1514 ,1610 ,1707 ,1804 ,1902 ,
2000 ,2098 ,2196 ,2293 ,2390 ,2486 ,2581 ,2674 ,
2765 ,2855 ,2943 ,3028 ,3111 ,3191 ,3269 ,3343 ,
3414 ,3482 ,3546 ,3606 ,3663 ,3715 ,3764 ,3808 ,
3848 ,3883 ,3914 ,3940 ,3962 ,3978 ,3990 ,3998
};
void TIM_Int_Init(u16 arr,u16 psc)
{
RCC->APB1ENR|=1<<0; //TIM2时钟使能
TIM2->ARR=arr;
TIM2->PSC=psc;
TIM2->CR1|=1<<7;
TIM2->CR2 |=0x2<<4; //TIMER更新作为TRGO源
TIM2->CR1 |=TIM_CR1_CEN;
TIM6->ARR=arr; //TIM6的时钟在前面系统初始化的时候已经开启了,这里不在重复开启,不影响问题的本质
TIM6->PSC=psc;
TIM6->CR1|=1<<7;
TIM6->CR2 |=0x2<<4;
TIM6->CR1 |=TIM_CR1_CEN;
}
void DAC_DMA_init(void)
{
DMA_InitTypeDef DMA_InitStructure;
DMA_DeInit(DMA1_Stream5);
DMA_InitStructure.DMA_Channel = DMA_Channel_7;
DMA_InitStructure.DMA_PeripheralBaseAddr = DAC1_DMA_ADDR;
DMA_InitStructure.DMA_Memory0BaseAddr = (u32)DAC_cosTAB;//
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
DMA_InitStructure.DMA_BufferSize =128;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;//
DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Word;//
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;// ;
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_FIFOMode=DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold=DMA_FIFOThreshold_1QuarterFull;
DMA_InitStructure.DMA_MemoryBurst=DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst=DMA_PeripheralBurst_Single;
DMA_Init(DMA1_Stream5, &DMA_InitStructure);
DMA_Cmd(DMA1_Stream5, ENABLE);
///////////////////////////////////////////////////////////////////////////////////////////////////////
DMA_DeInit(DMA1_Stream6);
DMA_InitStructure.DMA_Channel = DMA_Channel_7;
DMA_InitStructure.DMA_PeripheralBaseAddr = DAC2_DMA_ADDR;
DMA_InitStructure.DMA_Memory0BaseAddr = (u32)DAC_sinTAB;//
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
DMA_InitStructure.DMA_BufferSize =128;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;//
DMA_InitStructure.DMA_MemoryDataSize = DMA_PeripheralDataSize_Word;//
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;// ;
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_FIFOMode=DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold=DMA_FIFOThreshold_1QuarterFull;
DMA_InitStructure.DMA_MemoryBurst=DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst=DMA_PeripheralBurst_Single;
DMA_Init(DMA1_Stream6, &DMA_InitStructure);
DMA_Cmd(DMA1_Stream6, ENABLE);
}
void Dac1_Init(void)
{
DAC_InitTypeDef DAC_InitStructure;
RCC->APB1ENR|=1<<29; // DAC时钟开启
DAC_DeInit();
DAC_StructInit(&DAC_InitStructure);
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;//
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable; //
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;//
DAC_Init(DAC_Channel_1, &DAC_InitStructure); //
DAC_Cmd(DAC_Channel_1, ENABLE); //
DAC_DMACmd(DAC_Channel_1, ENABLE); //
DAC_StructInit(&DAC_InitStructure);
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;//
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable; //
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T2_TRGO;//DAC
DAC_Init(DAC_Channel_2, &DAC_InitStructure); //
DAC_Cmd(DAC_Channel_2, ENABLE); //
DAC_DMACmd(DAC_Channel_2, ENABLE); //
DAC_DMA_init();
TIM_Int_Init(100,0);
}
void DDS_Output_Wave( u16 frq )
{
TIM2->ARR = frq;
TIM6->ARR = frq;
}
说明:在初始化的时候,只要调用Dac1_Init()就OK了,想要改变波形频率,只要调用 DDS_Output_Wave( u16 frq )函数,改变frq的值就OK 了。
问题再重申一下,就是当frq的值低于15的时候,就出问题了,通道一只有高电平,没有波形输出,但是通道2正常。请大神指点帮助。谢谢
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