Posted by Jantz on 2018-11-26 15:03

I’m trying to read ADC value and display it on the lcd when there is and voltage input.
But it would only give me random number when i run this code on the board.
Is there anything wrong?

1. include “stm32l4xx.h”
2. include “stm32l476g_discovery.h”
3. include “stm32l4xx_hal_adc.h”
4. include “stm32l4xx_hal_gpio.h”
5. include “adc.h”

////Internal variables
static GPIO_InitTypeDef pinconf;
static ADC_HandleTypeDef hadc;
static ADC_ChannelConfTypeDef sConfig;

////Internal functions
//Pin initialization.
static void ADC_GPIO_Init(){
__HAL_RCC_GPIOA_CLK_ENABLE();
pinconf.Pin = GPIO_PIN_0;
pinconf.Mode = GPIO_MODE_ANALOG;
pinconf.Pull = GPIO_NOPULL;
pinconf.Speed = GPIO_SPEED_FREQ_HIGH;
pinconf.Alternate = 0;
HAL_GPIO_Init(GPIOA,&pinconf);
}

//Handle initialization.
static void ADCHandle_Init(){
__HAL_RCC_ADC_CLK_ENABLE();
hadc.Instance = ADC2;
hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
hadc.Init.Resolution = ADC_RESOLUTION_12B;
hadc.Init.ScanConvMode = DISABLE;
hadc.Init.ContinuousConvMode = ENABLE;
hadc.Init.NbrOfConversion = 1;
hadc.Init.DiscontinuousConvMode = DISABLE;
hadc.Init.NbrOfDiscConversion = 0;
hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
HAL_ADC_Init(&hadc);
}

//Channel initialization.
static void ADCChannel_Init(){
sConfig.Channel = ADC_CHANNEL_1;
sConfig.SamplingTime = ADC_SAMPLETIME_12CYCLES_5;
sConfig.Rank = ADC_REGULAR_RANK_1;
sConfig.SingleDiff = ADC_SINGLE_ENDED;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
sConfig.Offset = 0;
HAL_ADC_ConfigChannel(&hadc,&sConfig);
}

////Exported functions
//ADC initialization.
void ADC_Init(){
ADC_GPIO_Init();
ADCHandle_Init();
ADCChannel_Init();
ADC_Enable(&hadc);
}

//Returns ADC value.
uint32_t getADCValue(void)
{
uint32_t value;
HAL_ADC_Start(&hadc);
while(HAL_ADC_PollForConversion(&hadc, 10)!= HAL_OK);
value = HAL_ADC_GetValue(&hadc);
HAL_ADC_Stop(&hadc);
return value;
}