TCS34725 with Blue Pill using STM32CubeIDE

Prerequisites

This project assumes you have already installed STM32CubeIDE. You need to have previously done a basic blink sketch with blue-pill using STM32CubeIDE. I have made a complete video from installing STM32CubeIDE to LED blink program. You can watch it by clicking this link. https://www.youtube.com/watch?v=kXg467nVd_A

Wiring Diagram

STM32CubeIDE Settings

Click connectivity --> Click I2C1

For I2C select I2C

Configuration --> Parameter Settings

For I2C speed select Fast Mode

Additional code on top of STM32CubeIDE generated code

/* USER CODE BEGIN 0 */
#define TCS34725_ADDRESS          (0x29 << 1) /* I2C address */
/* Datasheet is at https://cdn-shop.adafruit.com/datasheets/TCS34725.pdf */
#define TCS34725_COMMAND_BIT      (0x80)      /* Command bit */
#define TCS34725_ENABLE           (0x00)      /* Enable register */
#define TCS34725_ENABLE_AEN       (0x02)      /* RGBC Enable */
#define TCS34725_ENABLE_PON       (0x01)      /* Power on */
#define TCS34725_ATIME            (0x01)      /* Integration time */
#define TCS34725_CONTROL          (0x0F)      /* Set the gain level */
#define TCS34725_ID               (0x12)
/* 0x44 = TCS34721/TCS34725, 0x4D = TCS34723/TCS34727 */
#define TCS34725_CDATAL           (0x14)      /* Clear channel data */
#define TCS34725_CDATAH           (0x15)
#define TCS34725_RDATAL           (0x16)      /* Red channel data */
#define TCS34725_RDATAH           (0x17)
#define TCS34725_GDATAL           (0x18)      /* Green channel data */
#define TCS34725_GDATAH           (0x19)
#define TCS34725_BDATAL           (0x1A)      /* Blue channel data */
#define TCS34725_BDATAH           (0x1B)
/* set the correct delay time in void getRawData() for TCS34725_INTEGRATIONTIME */
#define TCS34725_INTEGRATIONTIME_50MS   0xEB  /* 50ms  - 20 cycles */
#define TCS34725_GAIN_4X                0x01  /* 4x gain  */

uint8_t _tcs34725Initialised = 0;
int red, green, blue;

void write8 (uint8_t reg, uint32_t value);
uint8_t read8(uint8_t reg);
uint16_t read16(uint8_t reg);
void enable(void);
void disable(void);
void setIntegrationTime(uint8_t it);
void setGain(uint8_t gain);
void tcs3272_init( void );
void getRawData (uint16_t *r, uint16_t *g, uint16_t *b, uint16_t *c);
void getRGB(int *R, int *G, int *B);

/* Writes a register and an 8 bit value over I2C */
void write8 (uint8_t reg, uint32_t value)
{
    uint8_t txBuffer[2];
    txBuffer[0] = (TCS34725_COMMAND_BIT | reg);
    txBuffer[1] = (value & 0xFF);
    HAL_I2C_Master_Transmit(&hi2c1, TCS34725_ADDRESS, txBuffer, 2, 100);
}

/* Reads an 8 bit value over I2C */
uint8_t read8(uint8_t reg)
{
    uint8_t buffer[1];
    buffer[0] = (TCS34725_COMMAND_BIT | reg);
    HAL_I2C_Master_Transmit(&hi2c1, TCS34725_ADDRESS, buffer, 1, 100);
    HAL_I2C_Master_Receive(&hi2c1, TCS34725_ADDRESS, buffer, 1, 100);
    return buffer[0];
}

/* Reads a 16 bit values over I2C */
uint16_t read16(uint8_t reg)
{
  uint16_t ret;
    uint8_t txBuffer[1],rxBuffer[2];
    txBuffer[0] = (TCS34725_COMMAND_BIT | reg);
    HAL_I2C_Master_Transmit(&hi2c1, TCS34725_ADDRESS, txBuffer, 1, 100);
    HAL_I2C_Master_Receive(&hi2c1, TCS34725_ADDRESS, rxBuffer, 2, 100);
    ret = rxBuffer[1];
    ret <<= 8;
    ret |= rxBuffer[0] & 0xFF;
  return ret;
}

void enable(void)
{
  write8(TCS34725_ENABLE, TCS34725_ENABLE_PON);
  HAL_Delay(3);
  write8(TCS34725_ENABLE, TCS34725_ENABLE_PON | TCS34725_ENABLE_AEN);
  HAL_Delay(50);
}

void disable(void)
{
  /* Turn the device off to save power */
  uint8_t reg = 0;
  reg = read8(TCS34725_ENABLE);
  write8(TCS34725_ENABLE, reg & ~(TCS34725_ENABLE_PON | TCS34725_ENABLE_AEN));
}

void setIntegrationTime(uint8_t itime)
{
  if (_tcs34725Initialised == 0) tcs3272_init();
  write8(TCS34725_ATIME, itime);
}

void setGain(uint8_t gain)
{
  if (_tcs34725Initialised == 0) tcs3272_init();
  write8(TCS34725_CONTROL, gain);
}

void tcs3272_init(void)
{
  /* Make sure we're actually connected */
  uint8_t readValue = read8(TCS34725_ID);
  if ((readValue != 0x44) && (readValue != 0x10))
  {
    return;
  }
  _tcs34725Initialised = 1;
  /* Set default integration time and gain */
  setIntegrationTime(TCS34725_INTEGRATIONTIME_50MS);
  setGain(TCS34725_GAIN_4X);
  /* Note: by default, the device is in power down mode on bootup */
  enable();
}

/* Get raw data */
void getRawData (uint16_t *r, uint16_t *g, uint16_t *b, uint16_t *c)
{
  if (_tcs34725Initialised == 0) tcs3272_init();

  *c = read16(TCS34725_CDATAL);
  *r = read16(TCS34725_RDATAL);
  *g = read16(TCS34725_GDATAL);
  *b = read16(TCS34725_BDATAL);
  /* Delay time is from page no 16/26 from the datasheet  (256 − ATIME)* 2.4ms */
  HAL_Delay(50); // Set delay for (256 − 0xEB)* 2.4ms = 50ms
}

/* Get Red, Green and Blue color from Raw Data */
void getRGB(int *R, int *G, int *B)
{
    uint16_t rawRed, rawGreen, rawBlue, rawClear;
    getRawData(&rawRed, &rawGreen, &rawBlue, &rawClear);
    if(rawClear == 0)
    {
      *R = 0;
      *G = 0;
      *B = 0;
    }
    else
    {
      *R = (int)rawRed * 255 / rawClear;
      *G = (int)rawGreen * 255 / rawClear;
      *B = (int)rawBlue * 255 / rawClear;
    }
}
/* USER CODE END 0 */

  /* USER CODE BEGIN WHILE */
  while (1)
  {
    getRGB(&red, &green, &blue);
    HAL_Delay(500);
    /* USER CODE END WHILE */