ADC+DMA 传输时读到的值都是0，不知道为什么

小白奇奇奇· · 发表于 2015-8-24 10:22:19

[mw_shl_code=c,true]void Adc_Init(void) { GPIO_InitTypeDef GPIO_InitStructure; ADC_CommonInitTypeDef ADC_CommonInitStructure; ADC_InitTypeDef ADC_InitStructure; RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);//使能GPIOA时钟 RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE); //使能ADC1时钟 //先初始化ADC1通道5 IO口 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;//PA5 通道5 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;//模拟输入 GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;//不带上下拉 GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化 RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,ENABLE); //ADC1复位 RCC_APB2PeriphResetCmd(RCC_APB2Periph_ADC1,DISABLE); //复位结束 ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;//独立模式 ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;//两个采样阶段之间的延迟5个时钟 ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_1; //DMA使能 ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;//预分频4分频。ADCCLK=PCLK2/4=84/4=21Mhz,ADC时钟最好不要超过36Mhz ADC_CommonInit(&ADC_CommonInitStructure);//初始化 ADC_InitStructure.ADC_Resolution = ADC_Resolution_8b;//8位模式 ADC_InitStructure.ADC_ScanConvMode = DISABLE;//非扫描模式 ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;//打开连续转换 ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;//禁止触发检测，使用软件触发 ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;//右对齐 ADC_InitStructure.ADC_NbrOfConversion = 1;//1个转换在规则序列中也就是只转换规则序列1 ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1; ADC_Init(ADC1, &ADC_InitStructure);//ADC初始化 ADC_RegularChannelConfig(ADC1,ADC_Channel_5, 1, ADC_SampleTime_3Cycles ); //ADC1,ADC通道,480个周期,提高采样时间可以提高精确度 ADC_DMARequestAfterLastTransferCmd(ADC1,ENABLE); ADC_DMACmd(ADC1,ENABLE); ADC_Cmd(ADC1, ENABLE);//开启AD转换器 // ADC_SoftwareStartConv(ADC1); //开启 ADC软件转换 } void MYDMA_Config(DMA_Stream_TypeDef *DMA_Streamx,u32 chx,u32 par,u32 mar,u16 ndtr) { DMA_InitTypeDef DMA_InitStructure; // NVIC_InitTypeDef NVIC_InitStructure; if((u32)DMA_Streamx>(u32)DMA2)//得到当前stream是属于DMA2还是DMA1 { RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2,ENABLE);//DMA2时钟使能 }else { RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1,ENABLE);//DMA1时钟使能 } DMA_DeInit(DMA_Streamx); while (DMA_GetCmdStatus(DMA_Streamx) != DISABLE){}//等待DMA可配置 /* 配置 DMA Stream */ DMA_InitStructure.DMA_Channel = chx; //通道选择 DMA_InitStructure.DMA_PeripheralBaseAddr = par;//DMA外设地址 DMA_InitStructure.DMA_Memory0BaseAddr = mar;//DMA存储器0地址 DMA_InitStructure.DMA_DIR =DMA_DIR_PeripheralToMemory;//存储器到外设模式 DMA_InitStructure.DMA_BufferSize = ndtr;//数据传输量 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//外设非增量模式 DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//存储器增量模式 DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外设数据长度:8位 DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//存储器数据长度:8位 DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;//使用普通模式 DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;//中等优先级 DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable; DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full; DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;//存储器突发单次传输 DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;//外设突发单次传输 DMA_Init(DMA_Streamx, &DMA_InitStructure);//初始化DMA Stream DMA_Cmd(DMA2_Stream0,ENABLE); /* DMA_ITConfig(DMA2_Stream0,DMA_IT_TC,ENABLE);//开启相关中断 //Usart1 NVIC 配置 NVIC_InitStructure.NVIC_IRQChannel = DMA2_Stream0_IRQn;//DMA2_Stream0中断通道 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;//抢占优先级3 NVIC_InitStructure.NVIC_IRQChannelSubPriority =1; //子优先级3 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能 NVIC_Init(&NVIC_InitStructure); //根据指定的参数初始化VIC寄存器 */ } //开启一次DMA传输 //DMA_Streamx

MA数据流,DMA1_Stream0~7/DMA2_Stream0~7 //ndtr:数据传输量 void MYDMA_Enable(DMA_Stream_TypeDef *DMA_Streamx,u16 ndtr) { DMA_Cmd(DMA_Streamx, DISABLE); //关闭DMA传输 while (DMA_GetCmdStatus(DMA_Streamx) != DISABLE){} //确保DMA可以被设置 DMA_SetCurrDataCounter(DMA_Streamx,ndtr); //数据传输量 DMA_Cmd(DMA_Streamx, ENABLE); //开启DMA传输 } int main(void) { NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);//设置系统中断优先级分组2 delay_init(168); //初始化延时函数 uart_init(115200); //初始化串口波特率为115200 LED_Init(); //初始化LED LCD_Init(); //初始化LCD Adc_Init(); //初始化ADC MYDMA_Config(DMA2_Stream0,DMA_Channel_0,(u32)&ADC1->DR,(u32)ADC_output,(FFT_LENGTH*3-1)); //DMA2,STEAM0,CH0,外设为ADC1,存储器为signal,长度为:SIGNAL_BUF_SIZE. ADC_SoftwareStartConv(ADC1); //开启 ADC软件转换 while(1) { u16 i=0; DMA_Cmd(DMA2_Stream0, ENABLE); //ADC_DMACmd(ADC1,ENABLE); //使能串口1的DMA发送 MYDMA_Enable(DMA2_Stream0,(FFT_LENGTH*3-1)); //开始一次DMA传输！ while(1) { if(DMA_GetFlagStatus(DMA2_Stream0,DMA_FLAG_TCIF0)!=RESET)//等待DMA2_Steam0传输完成 { DMA_ClearFlag(DMA2_Stream0,DMA_FLAG_TCIF0);//清除DMA2_Steam0传输完成标志 //printf("%f\r\n",1.233); for(i=0;i<3*FFT_LENGTH-1;i++) { ADC_outputbuf_down=(float)ADC_output;//*(1.0/1000); printf("%f\r\n",ADC_outputbuf_down); } break; } } } }[/mw_shl_code]