SHT30.h File Reference

SHT30 functionality. More...

#include <stdint.h>

Go to the source code of this file.

Functions
int8_t	softResetSHT30 (void)
	Soft reset the SHT30. More...
int32_t	SHT30_readTemp (void)
	Do I2C transfers to get the temperature from the SHT30. More...

Detailed Description

SHT30 functionality.

Version

1.0

Author

Modified by Brecht Van Eeckhoudt

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License

Copyright (C) 2020 - Brecht Van Eeckhoudt

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

A copy of the GNU General Public License can be found in the LICENSE file along with this source code.

Some methods use code obtained from examples from Silicon Labs' GitHub. These sections are licensed under the Silabs License Agreement. See the file "Silabs_License_Agreement.txt" for details. Before using this software for any purpose, you must agree to the terms of that agreement.

Definition in file SHT30.h.

Function Documentation

SHT30_readTemp()

int32_t SHT30_readTemp

(

void

)

Do I2C transfers to get the temperature from the SHT30.

This method also initializes i2C if necessary.

Returns

The temperature (*1000).

Definition at line 134 of file SHT30.c.

{
    /* Initialize I2C if not already the case */
    if (initI2C() != 0) return (-6);

    /* Separate command in two bytes (ANDing with a mask and shifting one byte (8 bits) per position) */
    uint8_t cmd_buf[2] = {(HIGH_REP_MEAS_CMD >> 8), (HIGH_REP_MEAS_CMD & 0x00FF)};

    /* Transfer structure */
    I2C_TransferSeq_TypeDef i2cTransfer;
    I2C_TransferReturn_TypeDef result;

    /* Create buffer for received bytes */
    uint8_t data_buf[6] = {0, 0, 0, 0, 0, 0};

    // data_buf[6] = cTemp msb, cTemp lsb, cTemp crc, humidity msb, humidity lsb, humidity crc
    // float cTemp = ((((data_buf[0] * 256.0) + data_buf[1]) * 175) / 65535.0) - 45;
    // float humidity = ((((data_buf[3] * 256.0) + data_buf[4]) * 100) / 65535.0);

    /* Initializing I2C transfer */
    i2cTransfer.addr          = SHT30_ADDRESS << 1; /* Left shift so we go to 8 bit notation instead of 7 */
    i2cTransfer.flags         = I2C_FLAG_WRITE; /* Data written from buf[0].data */
    i2cTransfer.buf[0].data   = cmd_buf;
    i2cTransfer.buf[0].len    = 2; /* Command is two bytes */
    result = I2C_TransferInit(BUS_I2C, &i2cTransfer);

    /* Transmitting I2C data (busy-wait until transfer is complete) */
    while (result == i2cTransferInProgress) result = I2C_Transfer(BUS_I2C);

    delay(10);

    /* Initializing I2C transfer */
    i2cTransfer.flags         = I2C_FLAG_READ; /* Data read into buf[0].data */
    i2cTransfer.buf[0].data   = data_buf;
    i2cTransfer.buf[0].len    = 6; /* Data itself is 6 bytes */
    result = I2C_TransferInit(BUS_I2C, &i2cTransfer);

    /* Transmitting I2C data (busy-wait until transfer is complete) */
    while (result == i2cTransferInProgress) result = I2C_Transfer(BUS_I2C);

    return ((int32_t)((((((data_buf[0] * 256.0) + data_buf[1]) * 175) / 65535.0) - 45) * 1000));
}

softResetSHT30()

int8_t softResetSHT30

(

void

)

Soft reset the SHT30.

This method also initializes i2C if necessary.

Note

This is a static method because it's only internally used in this file and called by other methods if necessary.

Returns

• 0 - Byte written correctly.
• -1 - i2cTransferNack, NACK received during transfer.
• -2 - i2cTransferBusErr, Bus error during transfer (misplaced START/STOP).
• -3 - i2cTransferArbLost, Arbitration lost during transfer.
• -4 - i2cTransferUsageFault, Usage fault.
• -5 - i2cTransferSwFault, SW fault.
• -6 - Coudldn't configure I2C.

Definition at line 91 of file SHT30.c.

{
    /* Initialize I2C if not already the case */
    if (initI2C() != 0) return (-6);

    /* Separate command in two bytes (ANDing with a mask and shifting one byte (8 bits) per position) */
    uint8_t cmd_buf[2] = {(SOFT_RESET_CMD >> 8), (SOFT_RESET_CMD & 0x00FF)};

    /* Transfer structure */
    I2C_TransferSeq_TypeDef i2cTransfer;
    I2C_TransferReturn_TypeDef result;

    /* Initializing I2C transfer */
    i2cTransfer.addr          = SHT30_ADDRESS << 1; /* Left shift so we go to 8 bit notation instead of 7 */
    i2cTransfer.flags         = I2C_FLAG_WRITE; /* Data written from buf[0].data */
    i2cTransfer.buf[0].data   = cmd_buf;
    i2cTransfer.buf[0].len    = 2; /* Command is two bytes */
    result = I2C_TransferInit(BUS_I2C, &i2cTransfer);

    /* Transmitting I2C data (busy-wait until transfer is complete) */
    while (result == i2cTransferInProgress) result = I2C_Transfer(BUS_I2C);

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
    dbinfo("Soft reset SHT30");
#endif /* DEBUG_DBPRINT */

    /* Indicate that SHT30 has been soft reset */
    SHT30_reset = true;

    return (result);
}