STM32 ADC Signal Output to Serial Plotter

This document provides a C/C++ code implementation for reading an analog signal using the ADC (Analog-to-Digital Converter) on an STM32 microcontroller and outputting the results to a serial plotter. The code is structured, well-commented, and adheres to best coding practices.

Key Components

1. ADC Initialization: Configure the ADC to read signals.
2. Serial Output Initialization: Setup UART for serial communication.
3. Main Loop: Continuously read from the ADC and output values to a serial plotter.

Required Libraries

Make sure you include the necessary headers based on your STM32 environment. Generally, these can be taken from STM32 HAL libraries.

#include "stm32f4xx_hal.h"   // Adjust based on your STM32 series
#include "usart.h"           // UART configuration
#include "adc.h"             // ADC configuration

ADC Configuration

Ensure the ADC is set up properly in the cubeMX configuration tool or manually in the code.

Code Implementation

Below is an example implementation.

#include "stm32f4xx_hal.h"   // STM32 HAL header
#include "usart.h"           // UART header
#include "adc.h"             // ADC header

// Function prototypes
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_ADC1_Init(void);
static void MX_USART2_UART_Init(void);

/**
 * @brief Main program entry point.
 * 
 * Initializes the system, configures peripherals and enters an infinite loop  
 * to read ADC values and print them to a serial plotter at regular intervals.
 */
int main(void) {
    // HAL Initialization
    HAL_Init();  
    SystemClock_Config();  

    // Initialize peripherals
    MX_GPIO_Init();
    MX_USART2_UART_Init();  
    MX_ADC1_Init();  

    // Variables for reading values
    uint32_t adcValue = 0;
    char buffer[20];

    while (1) {
        // Start ADC conversion
        HAL_ADC_Start(&hadc1);  
        
        // Poll for ADC conversion completion
        HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY);
        
        // Read the ADC value
        adcValue = HAL_ADC_GetValue(&hadc1);  

        // Send value to UART for serial plotting
        snprintf(buffer, sizeof(buffer), "%lu\r\n", adcValue);
        HAL_UART_Transmit(&huart2, (uint8_t *)buffer, strlen(buffer), HAL_MAX_DELAY);

        // Small delay to avoid excessive output
        HAL_Delay(500);
    }
}

/**
 * @brief System Clock Configuration.
 * 
 * Configures the system clock to the desired frequency.
 */
void SystemClock_Config(void) {
    // Implement your clock configuration here
}

/**
 * @brief Initialize ADC1.
 * 
 * Configures the ADC parameters.
 */
static void MX_ADC1_Init(void) {
    // ADC initialization code
    // ...
}

/**
 * @brief Initialize USART2.
 * 
 * Sets up the serial interface.
 */
static void MX_USART2_UART_Init(void) {
    // USART initialization code
    // ...
}

/**
 * @brief Initialize GPIO.
 * 
 * Sets up GPIO pins used for ADC and UART.
 */
static void MX_GPIO_Init(void) {
    // GPIO initialization code
    // ...
}

Explanation of the Code

1. Initialization:

   • HAL_Init(): Initialize the Hardware Abstraction Layer.
   • System clock configuration is handled in SystemClock_Config().

2. Peripheral Setup:

   • MX_GPIO_Init(): Initializes any GPIO pins required for ADC and UART.
   • MX_ADC1_Init(): Sets up the ADC parameters.
   • MX_USART2_UART_Init(): Configures the UART for serial communication.

3. ADC Reading:

   • In the infinite loop, the ADC starts conversion, waits for it to complete, retrieves the value, and sends it to the serial plotter via UART.

4. Buffering Output:

   • The ADC value is formatted into a buffer and transmitted to enable visualization in a serial plotter.

5. Efficiency:

   • A delay of 500 milliseconds is employed to control the frequency of output, preventing data overflow.

Conclusion

This code example provides a foundational setup for reading from an ADC on an STM32 microcontroller and outputting the data to a serial plotter. For further enhancements, consider implementing error handling and more sophisticated data processing.

Note

For more advanced techniques and features, consider exploring courses offered on the Enterprise DNA Platform, which delve deeper into STM32 programming and embedded systems development.