u0-decibels/Core/Src/main.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2025 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <stdio.h>
#include <qfplib-port.h>
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
typedef struct  {
    int32_t value : 18;
} sample_t;
/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define SAMPLE_COUNT        (256)   // Sample count per half-transfer
#define SAMPLES_PER_REPORT  (48000) // Report every second given our 48 kHz rate
#define MIC_OFFSET_DB       (  0.f) // Linear offset
#define MIC_SENSITIVITY     (-26.f) // dBFS value expected at MIC_REF_DB
#define MIC_REF_DB          ( 94.f) // dB where sensitivity is specified
#define MIC_BITS            (18)
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

SPI_HandleTypeDef hspi1;
DMA_HandleTypeDef hdma_spi1_rx;
DMA_HandleTypeDef hdma_spi1_tx;

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */
static const uint8_t I2S_Frame_Buffer[8] = {
  0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF
};
static uint8_t I2S_Receive_Buffer[SAMPLE_COUNT * 2 * sizeof(sample_t)];

float ln10;
float MIC_REF_AMPL;

static float DB_Sum_Squares = 0.f;
static unsigned DB_Count = 0;
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_SPI1_Init(void);
static void MX_USART2_UART_Init(void);
/* USER CODE BEGIN PFP */
static HAL_StatusTypeDef HAL_SPI_TransmitReceive_DMA_Mixed(
    SPI_HandleTypeDef *hspi,
    const uint8_t *pTxData,
    uint8_t *pRxData,
    uint16_t TxSize,
    uint16_t RxSize);
static void SPI_DMATransmitReceiveCplt(DMA_HandleTypeDef *hdma);
static void SPI_DMAHalfTransmitReceiveCplt(DMA_HandleTypeDef *hdma);
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
int __io_putchar(int ch)
{
    uint8_t buf = ch;
    HAL_UART_Transmit(&huart2, &buf, sizeof(buf), HAL_TIMEOUT);
    return buf;
}
/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */
  ln10 = qfp_fln(10.f);
  MIC_REF_AMPL = qfp_fmul(qfp_int2float((1 << (MIC_BITS - 1)) - 1),
    qfp_fpow(10.f, MIC_SENSITIVITY / 20.f));
  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_SPI1_Init();
  MX_USART2_UART_Init();
  /* USER CODE BEGIN 2 */
  __enable_irq();
  HAL_SPI_TransmitReceive_DMA_Mixed(&hspi1,
      I2S_Frame_Buffer,
      I2S_Receive_Buffer,
      sizeof(I2S_Frame_Buffer),
      sizeof(I2S_Receive_Buffer));
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    HAL_GPIO_WritePin(IDLE_GPIO_Port, IDLE_Pin, GPIO_PIN_SET);
    __WFI();
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Configure the main internal regulator output voltage
  */
  HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE2);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
  RCC_OscInitStruct.MSIState = RCC_MSI_ON;
  RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_9;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_MSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV2;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief SPI1 Initialization Function
  * @param None
  * @retval None
  */
static void MX_SPI1_Init(void)
{

  /* USER CODE BEGIN SPI1_Init 0 */

  /* USER CODE END SPI1_Init 0 */

  /* USER CODE BEGIN SPI1_Init 1 */

  /* USER CODE END SPI1_Init 1 */
  /* SPI1 parameter configuration*/
  hspi1.Instance = SPI1;
  hspi1.Init.Mode = SPI_MODE_MASTER;
  hspi1.Init.Direction = SPI_DIRECTION_2LINES;
  hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
  hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
  hspi1.Init.NSS = SPI_NSS_SOFT;
  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
  hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi1.Init.CRCPolynomial = 7;
  hspi1.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
  hspi1.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
  if (HAL_SPI_Init(&hspi1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN SPI1_Init 2 */

  /* USER CODE END SPI1_Init 2 */

}

/**
  * @brief USART2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_USART2_UART_Init(void)
{

  /* USER CODE BEGIN USART2_Init 0 */

  /* USER CODE END USART2_Init 0 */

  /* USER CODE BEGIN USART2_Init 1 */

  /* USER CODE END USART2_Init 1 */
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_8;
  huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart2.Init.ClockPrescaler = UART_PRESCALER_DIV1;
  huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_SetTxFifoThreshold(&huart2, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_SetRxFifoThreshold(&huart2, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_DisableFifoMode(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART2_Init 2 */

  /* USER CODE END USART2_Init 2 */

}

/**
  * Enable DMA controller clock
  */
static void MX_DMA_Init(void)
{

  /* DMA controller clock enable */
  __HAL_RCC_DMA1_CLK_ENABLE();

  /* DMA interrupt init */
  /* DMA1_Channel1_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);
  /* DMA1_Channel2_3_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);

}

/**
  * @brief GPIO Initialization Function
  * @param None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOD_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(LED_GREEN_GPIO_Port, LED_GREEN_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(LED_BLUE_GPIO_Port, LED_BLUE_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(LED_RED_GPIO_Port, LED_RED_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(IDLE_GPIO_Port, IDLE_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin : LED_GREEN_Pin */
  GPIO_InitStruct.Pin = LED_GREEN_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LED_GREEN_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : Joystick_Pin */
  GPIO_InitStruct.Pin = Joystick_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(Joystick_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : LED_BLUE_Pin */
  GPIO_InitStruct.Pin = LED_BLUE_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LED_BLUE_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : LED_RED_Pin */
  GPIO_InitStruct.Pin = LED_RED_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LED_RED_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : IDLE_Pin */
  GPIO_InitStruct.Pin = IDLE_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_MEDIUM;
  HAL_GPIO_Init(IDLE_GPIO_Port, &GPIO_InitStruct);

/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}

/* USER CODE BEGIN 4 */
HAL_StatusTypeDef HAL_SPI_TransmitReceive_DMA_Mixed(
    SPI_HandleTypeDef *hspi,
    const uint8_t *pTxData,
    uint8_t *pRxData,
    uint16_t TxSize,
    uint16_t RxSize)
{
  HAL_StatusTypeDef errorcode = HAL_OK;

  assert_param(IS_SPI_DMA_HANDLE(hspi->hdmarx));
  assert_param(IS_SPI_DMA_HANDLE(hspi->hdmatx));
  assert_param(IS_SPI_DIRECTION_2LINES(hspi->Init.Direction));

  __HAL_LOCK(hspi);

  hspi->State = HAL_SPI_STATE_BUSY_TX_RX;
  hspi->ErrorCode   = HAL_SPI_ERROR_NONE;
  hspi->pTxBuffPtr  = (uint8_t *)pTxData;
  hspi->TxXferSize  = TxSize;
  hspi->TxXferCount = TxSize;
  hspi->pRxBuffPtr  = (uint8_t *)pRxData;
  hspi->RxXferSize  = RxSize;
  hspi->RxXferCount = RxSize;
  hspi->RxISR       = NULL;
  hspi->TxISR       = NULL;

  /* Reset the threshold bit */
  CLEAR_BIT(hspi->Instance->CR2, SPI_CR2_LDMATX | SPI_CR2_LDMARX);

  /* Set RX Fifo threshold according the reception data length: 8bit */
  SET_BIT(hspi->Instance->CR2, SPI_RXFIFO_THRESHOLD);

  hspi->hdmarx->XferHalfCpltCallback = SPI_DMAHalfTransmitReceiveCplt;
  hspi->hdmarx->XferCpltCallback     = SPI_DMATransmitReceiveCplt;
  hspi->hdmarx->XferErrorCallback    = NULL;
  hspi->hdmarx->XferAbortCallback    = NULL;
  hspi->hdmatx->XferHalfCpltCallback = NULL;
  hspi->hdmatx->XferCpltCallback     = NULL;
  hspi->hdmatx->XferErrorCallback    = NULL;
  hspi->hdmatx->XferAbortCallback    = NULL;

  /* Enable the Rx DMA Stream/Channel  */
  errorcode = HAL_DMA_Start_IT(hspi->hdmarx, (uint32_t)&hspi->Instance->DR,
      (uint32_t)hspi->pRxBuffPtr, hspi->RxXferCount);
  if (HAL_OK != errorcode) {
    /* Update SPI error code */
    SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_DMA);
    goto error;
  }

  /* Enable Rx DMA Request */
  SET_BIT(hspi->Instance->CR2, SPI_CR2_RXDMAEN);

  /* Enable the Tx DMA Stream/Channel  */
  errorcode = HAL_DMA_Start_IT(hspi->hdmatx, (uint32_t)hspi->pTxBuffPtr,
      (uint32_t)&hspi->Instance->DR, hspi->TxXferCount);
  if (HAL_OK != errorcode) {
    /* Update SPI error code */
    SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_DMA);
    goto error;
  }

  /* Check if the SPI is already enabled */
  if ((hspi->Instance->CR1 & SPI_CR1_SPE) != SPI_CR1_SPE) {
    __HAL_SPI_ENABLE(hspi);
  }
  /* Enable the SPI Error Interrupt Bit */
  __HAL_SPI_ENABLE_IT(hspi, (SPI_IT_ERR));

  /* Enable Tx DMA Request */
  SET_BIT(hspi->Instance->CR2, SPI_CR2_TXDMAEN);

error :
  __HAL_UNLOCK(hspi);
  return errorcode;
}

void SPI_DMATransmitReceiveCplt(DMA_HandleTypeDef *hdma)
{
  SPI_HandleTypeDef *hspi = (SPI_HandleTypeDef *)hdma->Parent;
  (void)hspi;
}

static float process(float in_div4)
{
    static float z1 = 0, z2 = 0, z3 = 0, z5 = 0;

    float out1 = qfp_fadd(in_div4, z1);
    z1 = qfp_fadd(qfp_fmul(1.062f, out1), z2);
    z2 = qfp_fsub(qfp_fmul(-0.14f, out1), in_div4);

    float out2 = qfp_fadd(out1, z3);
    z3 = out1;

    float out3 = qfp_fadd(out2, z5);
    z5 = qfp_fsub(qfp_fmul(0.985f, out3), out2);

    return out3;
}

void SPI_DMAHalfTransmitReceiveCplt(DMA_HandleTypeDef *hdma)
{
  HAL_GPIO_WritePin(IDLE_GPIO_Port, IDLE_Pin, GPIO_PIN_RESET);

  SPI_HandleTypeDef *hspi = (SPI_HandleTypeDef *)hdma->Parent;
  (void)hspi;

  sample_t *sample = (sample_t *)I2S_Receive_Buffer;
  for (int i = 0; i < SAMPLE_COUNT / 8; i++) {
    float f = process(qfp_int2float(sample[i].value / 4));
    DB_Sum_Squares = qfp_fadd(DB_Sum_Squares, qfp_fmul(f, f));
  }
  DB_Count += SAMPLE_COUNT * 2; // Pretend we sampled the entire I2S buffer

  if (DB_Count > SAMPLES_PER_REPORT) {
    float rms = qfp_fsqrt(qfp_fdiv(DB_Sum_Squares, qfp_uint2float(DB_Count)));
    float db = qfp_fadd(MIC_OFFSET_DB + MIC_REF_DB, qfp_fmul(20.f,
      qfp_flog10(qfp_fdiv(rms, MIC_REF_AMPL))));
    DB_Sum_Squares = 0.f;
    DB_Count = 0;

    printf("%d dB\r\n", qfp_float2int(db));
  }
}
/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  __disable_irq();
  printf("Unhandled error, halting!\r\n");
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  printf("Wrong parameters value: file %s on line %d\r\n", file, line);
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */