2013-04-21 05:58 AM
I would like to use stm32f4 to measure a battery voltage, like AA1.5v
I connect the postive line to PC5 and gnd line to GND.I reference the example code on the Internet. But the code is stop at the while of adc flag. I don't know why it didn't work. If I delete the flag while. the adc value keep 0, it's not i want. I have no idea how to modify my code. And I use gnu tool to build the .bin file. Is it possible that I lose some important compile parameter?this is me code. thxuint32_t adcValue=0;uint32_t adcVoltage=0;int main(){ init_adc(); ADC_RegularChannelConfig(ADC1, ADC_Channel_16, 1, ADC_SampleTime_3Cycles); while(1){ //Start ADC1 Conversion ADC_SoftwareStartConv(ADC1); while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); adcValue= ADC_GetConversionValue(ADC1); adcVoltage = adcValue * (5.0/4096.0); }}void init_adc(){ ADC_InitTypeDef ADC_InitStructure; GPIO_InitTypeDef GPIO_InitStructure; ADC_CommonInitTypeDef ADC_CommonInitStructure; //Enable ADC1 RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE); //Enable the ADC1 GPIO Clock RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE); //Initializing GPIO for ADC GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_Init(GPIOC, &GPIO_InitStructure); //ADC Common Init //Use Independent mode ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent; ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2; ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled; ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles; ADC_CommonInit(&ADC_CommonInitStructure); //ADC1 Init ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b; ADC_InitStructure.ADC_ScanConvMode = DISABLE; ADC_InitStructure.ADC_ContinuousConvMode = DISABLE; ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None; ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right; ADC_InitStructure.ADC_NbrOfConversion = 1; ADC_Init(ADC1, &ADC_InitStructure); //Enabling Temperature sensor ADC_TempSensorVrefintCmd(ENABLE); //Enable ADC1 ADC_Cmd(ADC1, ENABLE);} #stm32f4-adc-battery2013-04-21 07:42 AM
You're not using 5V as a reference voltage.
You're mixing float and integer math. You're using the wrong channel. PC5 is channel 15 You should perhaps review the firmware examples more carefully,.2013-04-21 08:54 AM
thank you for your reply
but I try channel 15 to run adcit still block at the flag loop =(