STM32 ADC采用HSI时钟的问题，不准

木桩上的跛脚人提问时间：2019-9-2 18:15 /

问答
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各位大神，我这出现个问题，正常STM32103的片子，72M时钟的时候，ADC采样正常，当我准备降低部分功耗后，将时钟切换到HSI 8M时钟时，ADC采样的值，比72M时的值要高，如：采集电压，5V时。。。。。。。，72M时钟，，，采样ADC值为0x740；当前换到HSI 8M时，采样的ADC值为：0x790;求大神指点!

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21个回答

木桩上的跛脚人回答时间：2019-9-3 15:55:33

void ADCInit(void)
{
ADC_InitTypeDef ADC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;

//DMA channel1 configuration
ADC_Cmd(ADC1, DISABLE);
DMA_Cmd(DMA1_Channel1, DISABLE);

DMA_InitStructure.DMA_PeripheralBaseAddr = DR_ADDRESS;
DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&g_u32PowerADCValue;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = 3;

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; /* Éè¶¨ÄÚ´æµØÖ·µÝ¼Ó Ã¿´ÎDMA¶¼ÊÇ½«ÍâÉè¼Ä´æÆ÷ÖÐµÄÖµ´«µ½Á½¸öÄÚ´æ¿Õ¼äÖÐ */
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_DeInit(DMA1_Channel1);
DMA_Init(DMA1_Channel1, &DMA_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 = 3;
ADC_Init(ADC1, &ADC_InitStructure);

// ADC1 regular channel1 PA1 configuration
ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_1Cycles5);//

ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 2, ADC_SampleTime_1Cycles5); //
//
ADC_RegularChannelConfig(ADC1, ADC_Channel_16, 3, ADC_SampleTime_1Cycles5 );  //ADC1,ADC??3,?????,?????239.5??

ADC_TempSensorVrefintCmd(ENABLE);
// Enable ADC1 DMA
ADC_DMACmd(ADC1, ENABLE);

// Enable ADC1
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));

// Start ADC1 Software Conversion
ADC_SoftwareStartConvCmd(ADC1, ENABLE);

// Enable DMA channel1
DMA_Cmd(DMA1_Channel1, ENABLE);

}

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木桩上的跛脚人回答时间：2019-9-3 15:56:12

RCC_DeInit();

  RCC_HSICmd(ENABLE);

  while(RCC_GetFlagStatus(RCC_FLAG_HSIRDY) == RESET)
  {

  }

RCC_HCLKConfig(RCC_SYSCLK_Div1); //AHBÊ±ÖÓÎªÏµÍ³Ê±ÖÓSYSCLK

RCC_PCLK2Config(RCC_HCLK_Div2);  //APB1Ê±ÖÓÎªHCLK/2£¬ÆäÖÐHCLKÎªAHBÊ±ÖÓ

RCC_PCLK1Config(RCC_HCLK_Div1);  //APB2Ê±ÖÓÎªHCLK


//ÉèÖÃ PLL Ê±ÖÓÔ´¼°±¶ÆµÏµÊý

RCC_PLLConfig(RCC_PLLSource_HSI_Div2, RCC_PLLMul_2);

//Ê¹ÄÜ»òÕßÊ§ÄÜ PLL,Õâ¸ö²ÎÊý¿ÉÒÔÈ¡£ºENABLE»òÕßDISABLE

RCC_PLLCmd(ENABLE);//Èç¹ûPLL±»ÓÃÓÚÏµÍ³Ê±ÖÓ,ÄÇÃ´Ëü²»ÄÜ±»Ê§ÄÜ

//µÈ´ýÖ¸¶¨µÄ RCC ±êÖ¾Î»ÉèÖÃ³É¹¦ µÈ´ýPLL³õÊ¼»¯³É¹¦

while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
{

}
//ÉèÖÃÏµÍ³Ê±ÖÓ£¨SYSCLK£© ÉèÖÃPLLÎªÏµÍ³Ê±ÖÓÔ´
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
//µÈ´ýPLL³É¹¦ÓÃ×÷ÓÚÏµÍ³Ê±ÖÓµÄÊ±ÖÓÔ´

// 0x00£ºHSI ×÷ÎªÏµÍ³Ê±ÖÓ

// 0x04£ºHSE×÷ÎªÏµÍ³Ê±ÖÓ

// 0x08£ºPLL×÷ÎªÏµÍ³Ê±ÖÓ

while(RCC_GetSYSCLKSource() != 0x08)
{

}

// RCC_ADCCLKConfig(RCC_PCLK2_Div2);
}

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