STM32G474 ADC DMA

### STM32G474 ADC with DMA Configuration For configuring the ADC (Analog-to-Digital Converter) alongside DMA (Direct Memory Access) on an STM32G474 microcontroller, it involves setting up both peripherals correctly within a project environment such as one using CubeMX and PlatformIO for development purposes[^2]. The setup ensures that data conversion occurs efficiently while transferring results directly into memory without involving the CPU, making this approach highly effective and time-saving[^1]. #### Hardware Initialization via CubeMX To begin, utilize STM32CubeMX to configure hardware settings: - Select `ADC` from peripheral options. - Enable continuous mode if intending to perform repeated conversions automatically after each regular channel sequence completion. - Choose `DMA Request` under Advanced Settings; specify the direction as Peripheral to Memory since data moves from ADC registers to SRAM. This graphical tool simplifies initial configurations by generating initialization code tailored specifically towards chosen parameters. #### Software Implementation Using HAL Library After completing hardware configuration through CubeMX, proceed with software implementation leveraging the HAL library provided by STMicroelectronics. Below showcases how to initialize ADC along with enabling its associated DMA stream in C language: ```c #include "stm32g4xx_hal.h" // Define global variables here... extern ADC_HandleTypeDef hadc1; uint16_t adcValue; void SystemClock_Config(void); static void MX_GPIO_Init(void); static void MX_DMA_Init(void); static void MX_ADC1_Init(void); int main(void){ /* Reset of all peripherals, Initializes the Flash interface and Systick */ HAL_Init(); /* Configure the system clock */ SystemClock_Config(); /* Initialize all configured peripherals */ MX_GPIO_Init(); MX_DMA_Init(); // Important step before initializing ADC when using DMA MX_ADC1_Init(); // Start ADC calibration then start conversion if(HAL_OK != HAL_ADCEx_Calibration_Start(&hadc1)){ Error_Handler(__FILE__, __LINE__); } if(HAL_OK != HAL_ADC_Start_DMA(&hadc1, (uint32_t*)&adcValue, 1)){ Error_Handler(__FILE__, __LINE__); } while (1){} } /** * @brief This function handles ADC interrupt request. */ void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc){ // Process converted value stored in 'adcValue' variable } ``` In addition, ensure proper handling callbacks are defined according to application requirements. For instance, implementing `HAL_ADC_ConvCpltCallback()` allows executing specific tasks once conversion completes successfully. #### Data Processing Post Conversion Once values have been acquired via ADC channels utilizing DMA transfer mechanisms, processing may involve mapping raw readings onto desired scales or ranges depending upon intended usage scenarios. An example would be transforming 12-bit resolution outputs between 0–4095 down to fit within an 8-bit range spanning 0–255[^3]: ```c uint8_t map_adc_to_8bit(uint16_t adc_raw_value){ return ((adc_raw_value * 255UL) / 4095); } ```