bme680_stm32f446/Core/Src/main.c

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2023 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 "bme680.h"
/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
#define AMBIENT_TEMP_GUESS 19.0
#define HEATER_TARGET 300.0
/* USER CODE END PD */

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

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/
SPI_HandleTypeDef hspi2;

TIM_HandleTypeDef htim6;

UART_HandleTypeDef huart2;

/* USER CODE BEGIN PV */
double gBase = 8000; // 02NOV2023 //358714.656; // 27OCT2023 avg taken from clean room
double hBase = 40.0;
double tAmbient = 25.0*100.0; // was the integer value times 100 oC ?
double humidityScore;
double hWeight = 0.5;
double iaqPercent;
double iaqScore;
double eCO2Value;

double calc_air_q (double hRead, double tRead, double gRes)
{
	double humidityScore = 0;
	double gasScore = 0;
	double humidityOffset = hRead - hBase;         // Calculate the humidity offset from the baseline setting
	double ambTemp = (tAmbient / 100);
	double temperatureOffset = tRead - ambTemp;     // Calculate the temperature offset from the ambient temperature
	double humidityRatio = ((humidityOffset / hBase) + 1);
	double temperatureRatio = (temperatureOffset / ambTemp);

	// IAQ Calculations

	if (humidityOffset > 0) {                                       // Different paths for calculating the humidity score depending on whether the offset is greater than 0
		humidityScore = (100 - hRead) / (100 - hBase);
	}
	else {
		humidityScore = hRead / hBase;
	}
	humidityScore = humidityScore * hWeight * 100;

	double gasRatio = (gRes / gBase);
	if ( gasRatio > 1.0 ) {
		asm("nop");
		// problem the gas resistance should not be this high. This mean the
		// gBase is too low!
		gBase = gRes;
		gasRatio = (gRes / gBase); // heuristic for now learning how this works
	}

	if ((gBase - gRes) > 0) {                                            // Different paths for calculating the gas score depending on whether the offset is greater than 0
		gasScore = gasRatio * (100 * (1 - hWeight));
	}
	else {
		// Make sure that when the gas offset and humidityOffset are 0, iaqPercent is 95% - leaves room for cleaner air to be identified
		gasScore = (double)((int)((70 + (5 * (gasRatio - 1))+0.5)));
		if (gasScore > 75) {
			gasScore = 75;
		}
	}

	iaqPercent = (humidityScore + gasScore);               // Air quality percentage is the sum of the humidity (25% weighting) and gas (75% weighting) scores
	iaqScore = (100 - iaqPercent) * 5   ;                            // Final air quality score is in range 0 - 500 (see BME688 datasheet page 11 for details)

	// eCO2 Calculations

	//eCO2Value = 250 *  pow(2.718 /*Math.E*/, (0.012 * iaqScore));      // Exponential curve equation to calculate the eCO2 from an iaqScore input

	// Adjust eCO2Value for humidity and/or temperature greater than the baseline values
	// if (humidityOffset > 0) {
	//  if (temperatureOffset > 0) {
	//      eCO2Value = eCO2Value * (humidityRatio + temperatureRatio);
	//  }
	//  else {
	//      eCO2Value = eCO2Value * humidityRatio;
	//   }
	//}
	// else if (temperatureOffset > 0) {
	//     eCO2Value = eCO2Value * (temperatureRatio + 1);
	//}
	//
	// If measurements are taking place rapidly, breath detection is possible due to the sudden increase in humidity (~7-10%)
	// If this increase happens within a 5s time window, 1200ppm is added to the eCO2 value
	// (These values were based on 'breath-testing' with another eCO2 sensor with algorithms built-in)
	//if ((measTime - measTimePrev) <= 5000) {
	// if ((hRead - hPrev) >= 3) {
	//     eCO2Value = eCO2Value + 1500;
	// }
	//}

	// eCO2Value = Math.trunc(eCO2Value);
	if (iaqScore < 0)
		asm ("nop");
	return iaqScore;
}
/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
static void MX_SPI2_Init(void);
static void MX_TIM6_Init(void);
/* USER CODE BEGIN PFP */



// Assumes TIMER6 is set to count every 1uS and that it wraps around (or counts up to 65535)
// and that it counts UP.
void delay_micro_seconds(uint32_t period) {
	int16_t a,then,now = *&htim6.Instance->CNT;
	asm(" nop");
	do {
		 then = *&htim6.Instance->CNT;
	}
	while ( (a=(then - now)) < period ); // hows about all that then.
	asm(" nop");
}

int BME680init() { return 0; }
int BME680deinit() { return 0; }

int  BME680_read_spi(uint8_t reg, uint8_t *dst, uint32_t size){

	uint8_t Tx[2];
	Tx[0] = reg | 0x80;
	Tx[1] = 0;

	HAL_GPIO_WritePin(GPIOC, GPIO_PIN_3, GPIO_PIN_RESET); // NSS low
	//HAL_SPI_TransmitReceive(&hspi2, Tx, dst, size, 1000); // timeout 1000msec;
	HAL_SPI_Transmit(&hspi2, &reg, 1, 1000);
	HAL_SPI_Receive(&hspi2, dst, size, 1000);
	HAL_GPIO_WritePin(GPIOC, GPIO_PIN_3, GPIO_PIN_SET); // NSS high
	return 0;
}



int BME680_write_spi(uint8_t reg, uint8_t value)
{
	int8_t Tx[2],Rx[2];
	int32_t hal_status;

	Tx[0] = reg & 0x7F;
	Tx[1] = value;

	HAL_GPIO_WritePin(GPIOC, GPIO_PIN_3, GPIO_PIN_RESET); // NSS low
	hal_status = HAL_SPI_Transmit(&hspi2, Tx, 2, 1000);
	while(&hspi2.State == HAL_SPI_STATE_BUSY); // wait for xmission complete
	HAL_GPIO_WritePin(GPIOC, GPIO_PIN_3, GPIO_PIN_SET); // NSS high

	return 0;
}
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */
	bme680_t bme680;
	uint8_t mode;
	int i;
	int error = 0;
  /* 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_USART2_UART_Init();
  MX_SPI2_Init();
  MX_TIM6_Init();
  /* USER CODE BEGIN 2 */

  // start TIM6 used for sleeping
  HAL_TIM_Base_Start(&htim6);

	bme680.dev.init   = BME680init;
	bme680.dev.read   = BME680_read_spi;
	bme680.dev.write  = BME680_write_spi;
	bme680.dev.deinit = BME680deinit;
	bme680.dev.sleep = delay_micro_seconds;

	/* 2. set the device mode */
	mode = BME680_MODE_FLOAT | BME680_SPI | BME680_ENABLE_GAS;
	/*     BME680_MODE_INT   | BME680_I2C; */


	/* 3. initialise dev func's, and check device id */
	if (bme680_init(&bme680, mode) != 0) {
		asm("nop");
		error = 1;
	}

	/* 4. reset device */
	bme680_reset(&bme680);

	/* 5. read calibration parameters from the device and store in memory */
	if (bme680_calibrate(&bme680) != 0) {
		bme680_deinit(&bme680);
		asm("nop");
		error = 2;
	}

	/* debug */
	bme680_print_calibration(&bme680);

	/* 6. set up device config */
	bme680.cfg.osrs_t = BME680_OVERSAMPLE_X16;
	bme680.cfg.osrs_p = BME680_OVERSAMPLE_X16;
	bme680.cfg.osrs_h = BME680_OVERSAMPLE_X8;
	bme680.cfg.filter = BME680_IIR_COEFF_127;

	/* configuring gas sensor. */
	/* NB: mode |= BME680_ENABLE_GAS; */
	/* there are 10 possible heater setpoints */
	/* they can be thought of as frames that define one single gas-resistance measurement */
	/* they do not carry over or affect each other in any way. */
	for(i=0; i<10; i++) {

		/* calculate a resistance target, based on desired temp, and ambient temp */
		bme680.cfg.res_heat[i] = bme680_calc_target(&bme680, HEATER_TARGET, AMBIENT_TEMP_GUESS);

		/* initial heating current for the setpoint. Could be useful in cold places or short gas_wait durations */
		/* 7-bit word. Each step/lsb is equiv. to 1/8 mA; so max 16 mA */
		/* a value of 20 would be equal to 2.5 mA */
		/* this s.p. field is allowed to be left as 0 if no preload is required. */
		bme680.cfg.idac_heat[i] = BME680_IDAC(100);

		/* define the time between the start of heating and start of resistance sensing in this s.p.*/
		/* Bosch datasheet suggests ~30 - 40ms is usually all that is required to get up to temp. */
		/* ^ probably with a good idac_heat current but doesn't mention it. */
		/* 25 * X4 = 100 ms wait before sampling resistance starts. */
		/* the first value is 6-bit (0...63) with 1 ms step size. */
		bme680.cfg.gas_wait[i] = BME680_GAS_WAIT(25, BME680_GAS_WAIT_X4);
	}

	/* The BME680 does not cycle between setpoints. They have to be manually set. */
	/* After each "run", the setpoint has to be changed. */
	/* the func bme680_write_setpoint_index() will write this field to the dev, without having to reconfigure */
	bme680.setpoint = 0; /* 0 thru 9 */

	/* 7. write config to device */
	if (bme680_configure(&bme680) != 0) {

		bme680_deinit(&bme680);
		error = 3;

	}


	int counter = 0;

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
		/* 8. Start forced measurement*. After it finishes, it should remember the previous config. */
		/*           * = bosch speak for one single T, P, H, GasRes measuring cycle. */
		if (bme680_start(&bme680) != 0) {

			error = 4;
			bme680_deinit(&bme680);

		}

		/* 9. poll the meas_status register until all scheduled conversions are done */
		/* this step can be skipped with SPI interrupt (3 wire SPI only. See 5.3.1.1 in datasheet; pg 29) */
		if (bme680_poll(&bme680) != 0) {
			error = 5;
			bme680_deinit(&bme680);

		}

		/* 10. read the ADC's and perform a conversion */
		if (bme680_read(&bme680) != 0) {

			error = 6;
			bme680_deinit(&bme680);

		}

		double airq = calc_air_q(bme680.fcomp.hum, bme680.fcomp.temp, bme680.fcomp.gas_res);
		if (counter++ > 100) {
			counter = 0;
			asm("nop");
		}
    /* 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_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE3);

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLM = 16;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
  RCC_OscInitStruct.PLL.PLLQ = 2;
  RCC_OscInitStruct.PLL.PLLR = 2;
  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_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief SPI2 Initialization Function
  * @param None
  * @retval None
  */
static void MX_SPI2_Init(void)
{

  /* USER CODE BEGIN SPI2_Init 0 */

  /* USER CODE END SPI2_Init 0 */

  /* USER CODE BEGIN SPI2_Init 1 */

  /* USER CODE END SPI2_Init 1 */
  /* SPI2 parameter configuration*/
  hspi2.Instance = SPI2;
  hspi2.Init.Mode = SPI_MODE_MASTER;
  hspi2.Init.Direction = SPI_DIRECTION_2LINES;
  hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
  hspi2.Init.CLKPhase = SPI_PHASE_1EDGE;
  hspi2.Init.NSS = SPI_NSS_SOFT;
  hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_16;
  hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
  hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
  hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
  hspi2.Init.CRCPolynomial = 10;
  if (HAL_SPI_Init(&hspi2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN SPI2_Init 2 */

  /* USER CODE END SPI2_Init 2 */

}

/**
  * @brief TIM6 Initialization Function
  * @param None
  * @retval None
  */
static void MX_TIM6_Init(void)
{

  /* USER CODE BEGIN TIM6_Init 0 */

  /* USER CODE END TIM6_Init 0 */

  TIM_MasterConfigTypeDef sMasterConfig = {0};

  /* USER CODE BEGIN TIM6_Init 1 */

  /* USER CODE END TIM6_Init 1 */
  htim6.Instance = TIM6;
  htim6.Init.Prescaler = 84-1;
  htim6.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim6.Init.Period = 65535;
  htim6.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim6) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim6, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM6_Init 2 */

  /* USER CODE END TIM6_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_16;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN USART2_Init 2 */

  /* USER CODE END USART2_Init 2 */

}

/**
  * @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_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOC, GPIO_PIN_3, GPIO_PIN_RESET);

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(LD2_GPIO_Port, LD2_Pin, GPIO_PIN_RESET);

  /*Configure GPIO pin : B1_Pin */
  GPIO_InitStruct.Pin = B1_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(B1_GPIO_Port, &GPIO_InitStruct);

  /*Configure GPIO pin : PC3 */
  GPIO_InitStruct.Pin = GPIO_PIN_3;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : LD2_Pin */
  GPIO_InitStruct.Pin = LD2_Pin;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(LD2_GPIO_Port, &GPIO_InitStruct);

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

/* USER CODE BEGIN 4 */

/* 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 */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  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 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */