我的硬件是这样连接的:PC0-PC4是模拟输入,现在我在这几个输入源上,不管电压怎么变化,我发现ADC出来的数据都是没有改变。
事实上,通道0,1,3的数据都是0x0fff,其它两通道的数据虽然不是0x0fff,但是很明显不是实际的电压值.
/* Configure PC.0-PC.4 as analog input --------------*/
GPIO_InitStructure.GPIO_Pin = 0x001f;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOC, &GPIO_InitStructure);
/* ADC1 configuration ------------------------------------------------------*/
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = ENABLE;
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 5;
ADC_Init(ADC1, &ADC_InitStructure);
/* ADC1 regular channels configuration */
ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_239Cycles5);
ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 2, ADC_SampleTime_239Cycles5);
ADC_RegularChannelConfig(ADC1, ADC_Channel_2, 3, ADC_SampleTime_239Cycles5);
ADC_RegularChannelConfig(ADC1, ADC_Channel_3, 4, ADC_SampleTime_239Cycles5);
ADC_RegularChannelConfig(ADC1, ADC_Channel_4, 5, ADC_SampleTime_239Cycles5);
DMA_DeInit(DMA1_Channel1);
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_Address;
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)ADC_ConvertedValueTab;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = 40;
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_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel1, &DMA_InitStructure);
ADC_DMACmd(ADC1, ENABLE);
/* Enable ADC1 */
DMA_Cmd(DMA1_Channel1, ENABLE);
ADC_Cmd(ADC1, ENABLE);
/* Enable ADC1 reset calibaration register */
ADC_ResetCalibration(ADC1);
/* Check the end of ADC1 reset calibration register */
while(ADC_GetResetCalibrationStatus(ADC1));
/* Start ADC1 calibaration */
ADC_StartCalibration(ADC1);
/* Check the end of ADC1 calibration */
while(ADC_GetCalibrationStatus(ADC1));
ADC_SoftwareStartConvCmd(ADC1,ENABLE);
答案
RCC_APB2PeriphClockCmd,是不是这个函数没有调用,没有启动外设时钟。
估计不是
如果没有启动的话,ad的数据是出不来的。
时钟已经设置了
RCC_HCLKConfig (RCC_SYSCLK_Div1); /* HCLK = SYSCLK */
RCC_PCLK2Config (RCC_HCLK_Div1); /* PCLK2 = HCLK */
RCC_PCLK1Config (RCC_HCLK_Div2); /* PCLK1 = HCLK/2 */
RCC_ADCCLKConfig (RCC_PCLK2_Div8); /* ADCCLK = PCLK2/8 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ALL,ENABLE);
会不会存在这样的问题?
我用的是STM32F103VC:
PC0-PC4可以作为ADC_Channel_0 - ADC_Channel_4的模拟输入,PA0-PA4也可以作为ADC_Channel_0 - ADC_Channel_4的模拟输入,所以,它会不会把PA0-PA4作为ADC_Channel_0 - ADC_Channel_4的模拟输入,而不是我期望的PC0-PC4?
你搞错了吧?PC0~PC4是ADC输入10~14,PA0~PA4才是ADC输入0~4
注意:STM32F103VC的数据手册中表5有这样的注释
PC0对应ADC123_IN10,这表示ADC1_IN10、ADC2_IN10和ADC3_IN10共用这个引脚。
同样PC1对应ADC123_IN11;PC2对应ADC123_IN12;PC3对应ADC123_IN13;PC4对应ADC12_IN14,PC4只对应ADC1和ADC2的模拟输入14,没有对应ADC3。
请下载最新的数据手册:
相关链接:
http://www.st.com/stonline/products/literature/ds/14611.pdf