本帖最后由 abnsl 于 2019-7-23 15:45 编辑
STM32F373的ADC采样问题，必须采样转换2次才有数据，什么原因？
void AI_ADCInit(void)
{
GPIO_InitTypeDef GPIO_InitStruct;
ADC_InitTypeDef ADC_InitStruct;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
RCC_ADCCLKConfig(RCC_PCLK2_Div6);//72M/6=12, ADC²ÉÑù×î¸ßƵÂÊ14MHz
GPIO_InitStruct.GPIO_Pin=GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3;
GPIO_InitStruct.GPIO_Mode=GPIO_Mode_AN;
//GPIO_InitStruct.GPIO_Speed=GPIO_Speed_50MHz;
//GPIO_InitStruct.GPIO_OType=GPIO_OType_PP;
//GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStruct);
//=======================================
ADC_DeInit(ADC1);
ADC_StructInit(&ADC_InitStruct);
/* initialize the ADC_ScanConvMode member */
ADC_InitStruct.ADC_ScanConvMode = DISABLE;
/* Initialize the ADC_ContinuousConvMode member */
ADC_InitStruct.ADC_ContinuousConvMode = DISABLE;
/* Initialize the ADC_ExternalTrigConv member */
ADC_InitStruct.ADC_ExternalTrigConv =ADC_ExternalTrigConv_T19_TRGO;
/* Initialize the ADC_DataAlign member */
ADC_InitStruct.ADC_DataAlign = ADC_DataAlign_Right;
/* Initialize the ADC_NbrOfChannel member */
ADC_InitStruct.ADC_NbrOfChannel = 1;
ADC_Init(ADC1,&ADC_InitStruct);
void AI_excute(void)
{
uint16_t i=0,j=0,num=0;
if((num=Order[1]&0x02))
{
printf("AI2 in !\r\n");
ADC_RegularChannelConfig(ADC1,ADC_Channel_3,1,ADC_SampleTime_239Cycles5);
ADC_Cmd(ADC1,ENABLE);
ADC_ResetCalibration(ADC1);
while(ADC_GetResetCalibrationStatus(ADC1));
ADC_StartCalibration(ADC1);
while(ADC_GetCalibrationStatus(ADC1));
ADC_Cmd(ADC1,ENABLE);//使能第二次
ADC_ClearFlag(ADC1,ADC_FLAG_STRT);
ADC_SoftwareStartConv(ADC1);
while(ADC_GetFlagStatus(ADC1,ADC_FLAG_STRT));
while(ADC_GetFlagStatus(ADC1,ADC_FLAG_EOC));
Aivalue=ADC_GetConversionValue(ADC1);
delay_nms(200);
Aivalue=(Aivalue/4096)*3.3;
ADC_ClearFlag(ADC1,ADC_FLAG_EOC);//ADC_FLAG_EOC/ADC_FLAG_STR
printf("AI2 value is %f !\r\n",Aivalue);//--------------到这里输出还是0 ，这一次采样值为0
ADC_ClearFlag(ADC1,ADC_FLAG_STRT);
ADC_SoftwareStartConv(ADC1);
while(ADC_GetFlagStatus(ADC1,ADC_FLAG_STRT));
while(ADC_GetFlagStatus(ADC1,ADC_FLAG_EOC));
Aivalue=ADC_GetConversionValue(ADC1);
delay_nms(200);
Aivalue=(Aivalue/4096)*3.3;//-------------------到这里采样就正常了，考虑过是否是采样时间延时不够，但好像不是这个问题。
}
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