si7021.c

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/***************************************************************************/
#include "i2cspm.h"

#include "thunderboard/util.h"
#include "thunderboard/board.h"
#include "thunderboard/si7021.h"

/***************************************************************************/
 /**************************************************************************/
/***************************************************************************/
uint32_t SI7021_init( void )
{

   uint32_t status;
   uint8_t cmdReadId2[2] = SI7021_CMD_READ_ID_BYTE2;
   uint8_t deviceId[8];

   /* Enable the sensor and wait for it to become ready */
   BOARD_envSensEnable( true );
   UTIL_delay( 80 );

   /* Read and compare device ID */
   status = SI7021_cmdRead( cmdReadId2, 2, deviceId, 8 );
   if( status != SI7021_OK ) {
      return status;
   }

   if( deviceId[0] != SI7021_DEVICE_ID ) {
      return SI7021_ERROR_INVALID_DEVICE_ID;
   }

   return SI7021_OK;

}

/***************************************************************************/
void SI7021_deInit( void )
{

   return;

}

/***************************************************************************/
uint32_t SI7021_measure( uint32_t *rhData, int32_t *tData )
{

   uint32_t status;
   uint8_t cmd;
   uint8_t readData[2];
   uint32_t timeout;

   /* Start no-hold measurement */
   cmd = SI7021_CMD_MEASURE_RH_NO_HOLD;
   status = SI7021_cmdWrite( &cmd, 1, NULL, 0 );
   if( status != SI7021_OK ) {
      return status;
   }

   /* Wait for data to become ready */
   timeout = 10;
   while( timeout-- ) {

      status = SI7021_cmdRead( NULL, 0, readData, 2 );

      if( status == SI7021_OK ) {
         /* Data is ready */
         *rhData = ( (uint32_t) readData[0] << 8 ) + ( readData[1] & 0xfc );
         *rhData = ( ( ( *rhData ) * 15625L ) >> 13 ) - 6000;
         break;
      }
      else if( status == SI7021_ERROR_I2C_TRANSFER_NACK ) {
         /* Data not ready, sleep and try again */
         UTIL_delay( 10 );
      }
      else {
         /* Something else went wrong! */
         return status;
      }
   }

   if( timeout == 0 ) {
      return SI7021_ERROR_TIMEOUT;
   }

   cmd = SI7021_CMD_READ_TEMP;
   status = SI7021_cmdRead( &cmd, 1, readData, 2 );
   if( status != SI7021_OK )
      return status;

   *tData = ( (uint32_t) readData[0] << 8 ) + ( readData[1] & 0xfc );
   *tData = ( ( ( *tData ) * 21965L ) >> 13 ) - 46850;

   return SI7021_OK;

}

/***************************************************************************/
uint32_t SI7021_getFwRev( uint8_t *fwRev )
{

   uint32_t status;
   uint8_t cmdReadFwRev[2] = SI7021_CMD_READ_FW_REV;

   status = SI7021_cmdRead( cmdReadFwRev, 2, fwRev, 1 );

   return status;

}

/***************************************************************************/
uint32_t SI7021_cmdRead( uint8_t *cmd, size_t cmdLen, uint8_t *result, size_t resultLen )
{

   I2C_TransferSeq_TypeDef seq;
   I2C_TransferReturn_TypeDef ret;

   seq.addr = SI7021_I2C_BUS_ADDRESS << 1;

   if( cmdLen > 0 ) {

      seq.flags = I2C_FLAG_WRITE_READ;

      seq.buf[0].data = cmd;
      seq.buf[0].len  = cmdLen;
      seq.buf[1].data = result;
      seq.buf[1].len  = resultLen;
   }
   else {

      seq.flags = I2C_FLAG_READ;

      seq.buf[0].data = result;
      seq.buf[0].len  = resultLen;
   }

   ret = I2CSPM_Transfer( SI7021_I2C_DEVICE, &seq );

   if( ret == i2cTransferNack ) {

      return SI7021_ERROR_I2C_TRANSFER_NACK;
   }
   else if( ret != i2cTransferDone ) {

      return SI7021_ERROR_I2C_TRANSFER_FAILED;
   }

   return SI7021_OK;

}

/***************************************************************************/
uint32_t SI7021_cmdWrite( uint8_t *cmd, size_t cmdLen, uint8_t *data, size_t dataLen )
{

   I2C_TransferSeq_TypeDef seq;
   I2C_TransferReturn_TypeDef ret;

   seq.addr = SI7021_I2C_BUS_ADDRESS << 1;
   seq.buf[0].data = cmd;
   seq.buf[0].len = cmdLen;

   if( dataLen > 0 ) {

      seq.flags = I2C_FLAG_WRITE_WRITE;
      seq.buf[1].data = data;
      seq.buf[1].len = dataLen;
   }
   else {

      seq.flags = I2C_FLAG_WRITE;
   }

   ret = I2CSPM_Transfer( SI7021_I2C_DEVICE, &seq );

   if( ret == i2cTransferNack ) {

      return SI7021_ERROR_I2C_TRANSFER_NACK;
   }
   else if( ret != i2cTransferDone ) {

      return SI7021_ERROR_I2C_TRANSFER_FAILED;
   }

   return SI7021_OK;

}