//==============================================================================
int main(void)
//==============================================================================
{ // variables
u8t error = 0; //variable for error code. For codes see system.h
// u8t userRegister; //variable for user register
// bt endOfBattery; //variable for end of battery
nt16 sRH; //variable for raw humidity ticks
ft humidityRH; //variable for relative humidity[%RH] as float
nt16 sT; //variable for raw temperature ticks
ft temperatureC; //variable for temperature[°C] as float
//u8t SerialNumber_SHT2x[8]; //64bit serial number
Grace_init();
//Init_HW(); //initializes Hardware (osc, watchdog,...)
I2c_Init(); //initializes uC-ports for I2C
DelayMicroSeconds(15000); //wait for sensor initialization t_powerUp (15ms)
//note: The following code segments show how to use the different functions
// of SHT2x. The loop does not show a typical sequence in an application
while(1)
{ error = 0; // reset error status
/* // --- Reset sensor by command ---
error |= SHT2x_SoftReset();
// --- Read the sensors serial number (64bit) ---
error |= SHT2x_GetSerialNumber(SerialNumber_SHT2x);
// --- Set Resolution e.g. RH 10bit, Temp 13bit ---
error |= SHT2x_ReadUserRegister(&userRegister); //get actual user reg
userRegister = (userRegister & ~SHT2x_RES_MASK) | SHT2x_RES_10_13BIT;
error |= SHT2x_WriteUserRegister(&userRegister); //write changed user reg
*/
// --- measure humidity with "Polling Mode" (no hold master) ---
error |= SHT2x_MeasurePoll(HUMIDITY, &sRH);
// --- measure temperature with "Polling Mode" (no hold master) ---
error |= SHT2x_MeasurePoll(TEMP, &sT);
//-- calculate humidity and temperature --
temperatureC = SHT2x_CalcTemperatureC(sT.u16);
humidityRH = SHT2x_CalcRH(sRH.u16);
/* // --- check end of battery status (eob)---
// note: a RH / Temp. measurement must be executed to update the status of eob
error |= SHT2x_ReadUserRegister(&userRegister); //get actual user reg
if( (userRegister & SHT2x_EOB_MASK) == SHT2x_EOB_ON ) endOfBattery = true;
else endOfBattery = false;
*/
}
}
//===========================================================================
u8t SHT2x_SoftReset()
//===========================================================================
{
u8t error=0; //error variable
I2c_StartCondition();
error |= I2c_WriteByte (I2C_ADR_W); // I2C Adr
error |= I2c_WriteByte (SOFT_RESET); // Command
I2c_StopCondition();
DelayMicroSeconds(15000); // wait till sensor has restarted
return error;
}
//===========================================================================
u8t SHT2x_MeasureHM(etSHT2xMeasureType eSHT2xMeasureType, nt16 *pMeasurand)
//===========================================================================
{
u8t checksum; //checksum
u8t data[2]; //data array for checksum verification
u8t error=0; //error variable
u16t i; //counting variable
//-- write I2C sensor address and command --
I2c_StartCondition();
error |= I2c_WriteByte (I2C_ADR_W); // I2C Adr
switch(eSHT2xMeasureType)
{
case HUMIDITY:
error |= I2c_WriteByte (TRIG_RH_MEASUREMENT_HM);
break;
case TEMP :
error |= I2c_WriteByte (TRIG_T_MEASUREMENT_HM);
break;
default:
assert(0);
}
//-- wait until hold master is released --
I2c_StartCondition();
error |= I2c_WriteByte (I2C_ADR_R);
SCL=HIGH; // set SCL I/O port as input
for(i=0; i<1000; i++) // wait until master hold is released or
{ DelayMicroSeconds(1000); // a timeout (~1s) is reached
if (SCL_CONF==1) break;
}
//-- check for timeout --
if(SCL_CONF==0) error |= TIME_OUT_ERROR;
//-- read two data bytes and one checksum byte --
pMeasurand->s16.u8H = data[0] = I2c_ReadByte(ACK);
pMeasurand->s16.u8L = data[1] = I2c_ReadByte(ACK);
checksum=I2c_ReadByte(NO_ACK);
//-- verify checksum --
error |= SHT2x_CheckCrc (data,2,checksum);
I2c_StopCondition();
return error;
}
//===========================================================================
u8t SHT2x_MeasurePoll(etSHT2xMeasureType eSHT2xMeasureType, nt16 *pMeasurand)
//===========================================================================
{
u8t checksum; //checksum
u8t data[2]; //data array for checksum verification
u8t error=0; //error variable
u16t i=0; //counting variable
//-- write I2C sensor address and command --
I2c_StartCondition();
error |= I2c_WriteByte (I2C_ADR_W); // I2C Adr
switch(eSHT2xMeasureType)
{
case HUMIDITY:
error |= I2c_WriteByte (TRIG_RH_MEASUREMENT_POLL);
break;
case TEMP :
error |= I2c_WriteByte (TRIG_T_MEASUREMENT_POLL);
break;
default:
assert(0);
}
//-- poll every 10ms for measurement ready. Timeout after 20 retries (200ms)--
do
{ I2c_StartCondition();
DelayMicroSeconds(10000); //delay 10ms
if(i++ >= 20) break;
} while(I2c_WriteByte (I2C_ADR_R) == ACK_ERROR);
if (i>=20) error |= TIME_OUT_ERROR;
//-- read two data bytes and one checksum byte --
pMeasurand->s16.u8H = data[0] = I2c_ReadByte(ACK);
pMeasurand->s16.u8L = data[1] = I2c_ReadByte(ACK);
checksum=I2c_ReadByte(NO_ACK);
//-- verify checksum --
error |= SHT2x_CheckCrc (data,2,checksum);
I2c_StopCondition();
return error;
}
//==============================================================================
int main()
{
//==============================================================================
uint8_t error = 0;
uint8_t userRegister;
uint16_t sRH;
float humidityRH;
char humitityOutStr[21];
uint16_t sT;
float temperatureC;
char temperatureOutStr[21];
uint8_t SerialNumber_sht21[8];
I2c_Init();
{
error = 0;
error |= sht21_SoftReset();
//==============================================================================
error |= sht21_GetSerialNumber(SerialNumber_sht21);
//==============================================================================
error |= sht21_ReadUserRegister(&userRegister);
userRegister = (userRegister & ~sht21_RES_MASK) | sht21_RES_10_13BIT;
error |= sht21_WriteUserRegister(&userRegister);
//==============================================================================
error |= sht21_MeasureHM(HUMIDITY, &sRH);
//==============================================================================
error |= sht21_MeasurePoll(TEMP, &sT);
//==============================================================================
temperatureC = sht21_CalcTemperatureC(sT.u16);
humidityRH = sht21_CalcRH(sRH.u16);
printf(humitityOutStr, "Humidity RH:%6.2f %% ",humidityRH);
printf(temperatureOutStr, "Temperature:%6.2f€C",temperatureC);
DelayMicroSeconds(300000);
}
}