Thread: ADC Conversion to Voltage Value

  1. #1
    Registered User
    Join Date
    Oct 2019

    ADC Conversion to Voltage Value

    Good Morning, I am currently programming a ARM Nucleo board to read a ADC value and convert the value to decimal.

    I am using a 12 bit ADC which is then (hopefully) being converted into a float for me to eventually output. However this conversion does not seem to be working very well.

    #include <stm32f4xx.h>
    #include "PLL_Config.c"
    #include "ADC.h"
    #include "DAC.h"
    #include "lcd.h"
    unsigned short ADC_DATA;
    int main(void)
        init_ADC();        //config ADC
        init_DAC();        //config DAC
        while (1){
            ADC_DATA=read_adc();            //read value from ADC
            output_dac(ADC_DATA);    //send straight to DAC (DAC pin should replicate ADC pin)    
    void init_ADC(void)
        RCC->AHB1ENR|=RCC_AHB1ENR_GPIOCEN;    //GPIOC clock enable
        ADC_input_port->MODER|=(3u<<(2*ADC_input_pin));    //ADC input pin is analogue mode
        RCC->APB2ENR|=RCC_APB2ENR_ADC1EN;        //ADC clock enable
        ADC1->SQR1&=~ADC_SQR1_L;                        //set number of conversions per sequence to 1
        ADC1->SQR3&=~ADC_SQR3_SQ1;                    //clear channel select bits
        ADC1->SQR3|=ADC_Channel;                        //set channel
        ADC1->CR2|=ADC_CR2_ADON;                        //enable ADC
    unsigned short read_adc(void)
        ADC1->CR2|=ADC_CR2_SWSTART;                //start ADC conversion
        while((ADC1->SR&ADC_SR_EOC)==0){__NOP();}    //wait for ADC conversion complete
        return ADC1->DR;                                    //return converted value

  2. #2
    Registered User
    Join Date
    May 2009
    Since, you did not post any float conversion code, it will be hard to help you. Even if I wanted to help you.

    I suggest you state what is failing to work! As in this is the output but I expected this!

    Tim S.
    "...a computer is a stupid machine with the ability to do incredibly smart things, while computer programmers are smart people with the ability to do incredibly stupid things. They are,in short, a perfect match.." Bill Bryson

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