/*

 * i2c.h

 *

 *  Created on: Mar 7, 2017

 *      Author: Matthew Reed

 */

#ifndef INC_I2C_H_

#define INC_I2C_H_

#include "system.h"

extern I2C_HandleTypeDef i2c_handle;

void i2c_init(void);

bool i2c_send(uint16_t address, uint8_t* buffer, uint16_t length);

bool i2c_receive(uint16_t address, uint8_t* buffer, uint16_t length);

#endif /* INC_I2C_H_ */

#ifndef INC_SGP30_H_

#define INC_SGP30_H_

#include <stdbool.h>

#include "stm32f0xx_hal.h"

#include "i2c.h"

// the i2c address

#define SGP30_I2CADDR_DEFAULT 0x58     ///< SGP30 has only one I2C address

// commands and constants

#define SGP30_FEATURESET       0x0020  ///< The required set for this library

#define SGP30_CRC8_POLYNOMIAL  0x31    ///< Seed for SGP30's CRC polynomial

#define SGP30_CRC8_INIT        0xFF    ///< Init value for CRC

#define SGP30_WORD_LEN         2       ///< 2 bytes per word

bool sgp30_init(void);

bool sgp30_IAQinit(void);

bool sgp30_IAQmeasure(void);

bool sgp30_getIAQBaseline(uint16_t *eco2_base, uint16_t *tvoc_base);

bool sgp30_setIAQBaseline(uint16_t eco2_base, uint16_t tvoc_base);

bool sgp30_setHumidity(uint32_t absolute_humidity);

bool sgp30_readWordFromCommand(uint8_t command[], uint8_t commandLength, uint16_t delay, uint16_t *readdata, uint8_t readlen);

uint8_t sgp30_generateCRC(uint8_t data[], uint8_t datalen);

#endif /* INC_SGP30_H_ */

/*

 * i2c.c

 *

 *  Created on: Mar 7, 2017

 *      Author: Matthew Reed

 */

#include "i2c.h"

I2C_HandleTypeDef i2c_handle;

void i2c_init(void)

{

    i2c_handle.Instance = I2C1;

    i2c_handle.Init.Timing = 0x2000090E;

    i2c_handle.Init.OwnAddress1 = 0;

    i2c_handle.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;

    i2c_handle.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;

    i2c_handle.Init.OwnAddress2 = 0;

    i2c_handle.Init.OwnAddress2Masks = I2C_OA2_NOMASK;

    i2c_handle.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;

    i2c_handle.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;

    HAL_I2C_Init(&i2c_handle);

    //Configure Analog filter

    HAL_I2CEx_ConfigAnalogFilter(&i2c_handle, I2C_ANALOGFILTER_ENABLE);

}

bool i2c_send(uint16_t address, uint8_t* buffer, uint16_t length)

{

    bool result = true;

    HAL_I2C_Master_Transmit(&i2c_handle, address, buffer, length, 10000);

//    while(HAL_I2C_Master_Transmit(&i2c_handle, address, buffer, length, 10000) != HAL_OK)

//    {

//

//        if (HAL_I2C_GetError(&i2c_handle) != HAL_I2C_ERROR_AF)

//        {

//            result = false;

//        }

//    }

    return result;

}

bool i2c_receive(uint16_t address, uint8_t* buffer, uint16_t length)

{

    bool result = true;

    HAL_I2C_Master_Receive(&i2c_handle, address, buffer, length, 10000);

//    while(HAL_I2C_Master_Receive(&i2c_handle, address, buffer, length, 10000) != HAL_OK)

//    {

//        if (HAL_I2C_GetError(&i2c_handle) != HAL_I2C_ERROR_AF)

//        {

//            result = false;

//        }

//    }

    return result;

}

void HAL_I2C_MasterTxCpltCallback(I2C_HandleTypeDef *I2cHandle)

{

}

void HAL_I2C_MasterRxCpltCallback(I2C_HandleTypeDef *I2cHandle)

{

}

void HAL_I2C_ErrorCallback(I2C_HandleTypeDef *I2cHandle)

{

}

#include "sgp30.h"

  /**

   * The last measurement of the IAQ-calculated Total Volatile Organic Compounds in ppb. This value is set when you call {@link IAQmeasure()}

   */

  uint16_t TVOC;

  /**

   * The last measurement of the IAQ-calculated equivalent CO2 in ppm. This value is set when you call {@link IAQmeasure()}

   */

  uint16_t eCO2;

  /**

   * The 48-bit serial number, this value is set when you call {@link begin()}

   */

  uint16_t serialnumber[3];

  uint8_t _i2caddr;

/**************************************************************************/

/*!

    @brief  Setups the hardware and detects a valid SGP30. Initializes I2C

    then reads the serialnumber and checks that we are talking to an SGP30

    @param  theWire Optional pointer to I2C interface, otherwise use Wire

    @returns True if SGP30 found on I2C, False if something went wrong!

*/

/**************************************************************************/

bool sgp30_init()

{

    _i2caddr = SGP30_I2CADDR_DEFAULT;

    i2c_init();

    uint8_t command[2];

    command[0] = 0x36;

    command[1] = 0x82;

    if (! sgp30_readWordFromCommand(command, 2, 10, serialnumber, 3))

        return false;

    uint16_t featureset;

    command[0] = 0x20;

    command[1] = 0x2F;

    if (! sgp30_readWordFromCommand(command, 2, 10, &featureset, 1))

        return false;

    //Serial.print("Featureset 0x"); Serial.println(featureset, HEX);

    if (featureset != SGP30_FEATURESET)

        return false;

    if (! sgp30_IAQinit())

        return false;

    return true;

}

uint16_t sgp30_get_tvoc(void)

{

    return TVOC;

}

uint16_t sgp30_get_eC02(void)

{

    return eCO2;

}

/**************************************************************************/

/*!

    @brief  Commands the sensor to begin the IAQ algorithm. Must be called after startup.

    @returns True if command completed successfully, false if something went wrong!

*/

/**************************************************************************/

bool sgp30_IAQinit(void)

{

    uint8_t command[2];

    command[0] = 0x20;

    command[1] = 0x03;

    return sgp30_readWordFromCommand(command, 2, 10, 0, 0);

}

/**************************************************************************/

/*!

    @brief  Commands the sensor to take a single eCO2/VOC measurement. Places results in {@link TVOC} and {@link eCO2}

    @returns True if command completed successfully, false if something went wrong!

*/

/**************************************************************************/

bool sgp30_IAQmeasure(void)

{

    uint8_t command[2];

    command[0] = 0x20;

    command[1] = 0x08;

    uint16_t reply[2];

    if (! sgp30_readWordFromCommand(command, 2, 12, reply, 2))

        return false;

    TVOC = reply[1];

    eCO2 = reply[0];

    return true;

}

/**************************************************************************/

/*!

    @brief Request baseline calibration values for both CO2 and TVOC IAQ calculations. Places results in parameter memory locaitons.

    @param eco2_base A pointer to a uint16_t which we will save the calibration value to

    @param tvoc_base A pointer to a uint16_t which we will save the calibration value to

    @returns True if command completed successfully, false if something went wrong!

*/

/**************************************************************************/

bool sgp30_getIAQBaseline(uint16_t *eco2_base, uint16_t *tvoc_base)

{

    uint8_t command[2];

    command[0] = 0x20;

    command[1] = 0x15;

    uint16_t reply[2];

    if (! sgp30_readWordFromCommand(command, 2, 10, reply, 2))

    return false;

    *eco2_base = reply[0];

    *tvoc_base = reply[1];

    return true;

}

/**************************************************************************/

/*!

    @brief Assign baseline calibration values for both CO2 and TVOC IAQ calculations.

    @param eco2_base A uint16_t which we will save the calibration value from

    @param tvoc_base A uint16_t which we will save the calibration value from

    @returns True if command completed successfully, false if something went wrong!

*/

/**************************************************************************/

bool sgp30_setIAQBaseline(uint16_t eco2_base, uint16_t tvoc_base)

{

    uint8_t command[8];

    command[0] = 0x20;

    command[1] = 0x1e;

    command[2] = tvoc_base >> 8;

    command[3] = tvoc_base & 0xFF;

    command[4] = sgp30_generateCRC(command+2, 2);

    command[5] = eco2_base >> 8;

    command[6] = eco2_base & 0xFF;

    command[7] = sgp30_generateCRC(command+5, 2);

    return sgp30_readWordFromCommand(command, 8, 10, 0, 0);

}

/**************************************************************************/

/*!

    @brief Set the absolute humidity value [mg/m^3] for compensation to increase precision of TVOC and eCO2.

    @param absolute_humidity A uint32_t [mg/m^3] which we will be used for compensation. If the absolute humidity is set to zero, humidity compensation will be disabled.

    @returns True if command completed successfully, false if something went wrong!

*/

/**************************************************************************/

bool sgp30_setHumidity(uint32_t absolute_humidity)

{

    if (absolute_humidity > 256000) {

        return false;

    }

    uint16_t ah_scaled = (uint16_t)(((uint64_t)absolute_humidity * 256 * 16777) >> 24);

    uint8_t command[5];

    command[0] = 0x20;

    command[1] = 0x61;

    command[2] = ah_scaled >> 8;

    command[3] = ah_scaled & 0xFF;

    command[4] = sgp30_generateCRC(command+2, 2);

    return sgp30_readWordFromCommand(command, 5, 10, 0, 0);

}

/**************************************************************************/

/*!

    @brief  I2C low level interfacing

*/

/**************************************************************************/

bool sgp30_readWordFromCommand(uint8_t command[], uint8_t commandLength, uint16_t delayms, uint16_t *readdata, uint8_t readlen)

{

    i2c_send(_i2caddr, command, commandLength);

    HAL_Delay(delayms);

    if (readlen == 0)

    return true;

    uint8_t replylen = readlen * (SGP30_WORD_LEN +1);

    uint8_t replybuffer[replylen];

    i2c_receive(_i2caddr, replybuffer, replylen);

    for (uint8_t i=0; i<readlen; i++) {

    uint8_t crc = sgp30_generateCRC(replybuffer+i*3, 2);

    if (crc != replybuffer[i * 3 + 2])

      return false;

    // success! store it

    readdata[i] = replybuffer[i*3];

    readdata[i] <<= 8;

    readdata[i] |= replybuffer[i*3 + 1];

    }

    return true;

}

uint8_t sgp30_generateCRC(uint8_t *data, uint8_t datalen)

{

    // calculates 8-Bit checksum with given polynomial

    uint8_t crc = SGP30_CRC8_INIT;

    for (uint8_t i=0; i<datalen; i++) {

    crc ^= data[i];

    for (uint8_t b=0; b<8; b++) {

        if (crc & 0x80)

            crc = (crc << 1) ^ SGP30_CRC8_POLYNOMIAL;

        else

            crc <<= 1;

        }

    }

    return crc;

}