/*---------------------------------------------------------------------------*/
#if 1 /* But ok! */
unsigned
sht11_sreg(void)
{
unsigned sreg, rcrc;
sstart(); /* Start transmission */
if(!swrite(STATUS_REG_R)) {
goto fail;
}
sreg = sread(1);
rcrc = sread(0);
#ifdef CRC_CHECK
{
unsigned crc;
crc = crc8_add(0x0, STATUS_REG_R);
crc = crc8_add(crc, sreg);
if (crc != rev8bits(rcrc))
goto fail;
}
#endif
return sreg;
fail:
sreset();
return -1;
}
/**
* Reads the current raw temperature value
*/
uint16_t sensirion::readTemperatureRaw()
{
uint16_t _val;
// Command to send to the SHT1x to request Temperature
const uint8_t _gTempCmd = 0b00000011;
if (millis() - _lastTempMillis < SHT_CACHE_MILLIS ){
return _lastTempRaw;
} else {
if ( sendCommandSHT(_gTempCmd, _dataPin, _clockPin) == SHT_SUCCESS ){
waitForResultSHT(_dataPin);
_val = getData16SHT(_dataPin, _clockPin);
uint8_t rxcrc = rev8bits( readCRC(_dataPin, _clockPin ) );
uint8_t mycrc = crc8add( 0, _gTempCmd );
mycrc = crc8add( mycrc, _val );
if (mycrc != rxcrc){
Serial.println("SHT: crc error");
Serial.print(" Got: 0x"); Serial.println(rxcrc, HEX);
Serial.print(" Expected: 0x"); Serial.println(mycrc, HEX);
return 0;
}
// cache
_lastTempMillis = millis();
_lastTempRaw = _val;
return (_val);
}
}
return 0; // error
}
/*
* Only commands MEASURE_HUMI or MEASURE_TEMP!
*/
static unsigned int
scmd(unsigned cmd)
{
unsigned int n;
if(cmd != MEASURE_HUMI && cmd != MEASURE_TEMP) {
PRINTF("Illegal command: %d\n", cmd);
return -1;
}
sstart(); /* Start transmission */
if(!swrite(cmd)) {
PRINTF("SHT11: scmd - swrite failed\n");
goto fail;
}
for(n = 0; n < 20000; n++) {
if(!SDA_IS_1) {
unsigned t0, t1, rcrc;
t0 = sread(1);
t1 = sread(1);
rcrc = sread(0);
PRINTF("SHT11: scmd - read %d, %d\n", t0, t1);
#ifdef CRC_CHECK
{
unsigned crc;
crc = crc8_add(0x0, cmd);
crc = crc8_add(crc, t0);
crc = crc8_add(crc, t1);
if(crc != rev8bits(rcrc)) {
PRINTF("SHT11: scmd - crc check failed %d vs %d\n",
crc, rev8bits(rcrc));
goto fail;
}
}
#endif
return (t0 << 8) | t1;
}
/* short wait before next loop */
clock_wait(1);
}
fail:
sreset();
return -1;
}
/**
* Reads current temperature-corrected relative humidity
*/
float sensirion::readHumidity()
{
uint16_t _val; // Raw humidity value returned from sensor
float _linearHumidity; // Humidity with linear correction applied
float _correctedHumidity; // Temperature-corrected humidity
float _temperature; // Raw temperature value
// Conversion coefficients from SHT15 datasheet
const float C1 = -4.0; // for 12 Bit
const float C2 = 0.0405; // for 12 Bit
const float C3 = -0.0000028; // for 12 Bit
const float T1 = 0.01; // for 14 Bit @ 5V
const float T2 = 0.00008; // for 14 Bit @ 5V
// Command to send to the SHT1x to request humidity
const uint8_t _gHumidCmd = 0b00000101;
// check cache
if ( millis() - _lastHumMillis < SHT_CACHE_MILLIS){
return _lastHumVal;
} else{
// Fetch the value from the sensor
if ( sendCommandSHT(_gHumidCmd, _dataPin, _clockPin) == SHT_SUCCESS ){
waitForResultSHT(_dataPin);
_val = getData16SHT(_dataPin, _clockPin);
uint8_t rxcrc = rev8bits( readCRC(_dataPin, _clockPin ) );
uint8_t mycrc = crc8add( 0, _gHumidCmd );
mycrc = crc8add( mycrc, _val );
if (mycrc != rxcrc){
Serial.println("SHT: crc error");
Serial.print(" Got: 0x"); Serial.println(rxcrc, HEX);
Serial.print(" Expected: 0x"); Serial.println(mycrc, HEX);
return NAN;
}
// Apply linear conversion to raw value
_linearHumidity = C1 + C2 * _val + C3 * _val * _val;
// Get current temperature for humidity correction
_temperature = readTemperatureC();
// Correct humidity value for current temperature
_correctedHumidity = (_temperature - 25.0 ) * (T1 + T2 * _val) + _linearHumidity;
// cache
_lastHumVal = _correctedHumidity;
_lastHumMillis = millis();
return (_correctedHumidity);
}
}
//error
return NAN;
}
/*
* Only commands MEASURE_HUMI or MEASURE_TEMP!
*/
static unsigned int
scmd(unsigned cmd)
{
unsigned long n;
if(cmd != MEASURE_HUMI && cmd != MEASURE_TEMP) {
return -1;
}
MCUCR |= (1<<JTD);
MCUCR |= (1<<JTD);
sreset();
/* Start transmission */
if(!swrite(cmd)) {
//printf("-2");
goto fail;
}
for(n = 0; n < 250000; n++) {
if(!SDA_IS_1) {
unsigned t0, t1, rcrc;
t0 = sread(1);
t1 = sread(1);
rcrc = sread(0);
//printf("t0:%d",t0);
//printf("t1:%d",t1);
#ifdef CRC_CHECK
{
unsigned crc;
crc = crc8_add(0x0, cmd);
crc = crc8_add(crc, t0);
crc = crc8_add(crc, t1);
if(crc != rev8bits(rcrc)) {
// printf("-3");
goto fail;
}
}
#endif
MCUCR &= (0<<JTD);
MCUCR &= (0<<JTD);
return (t0 << 8) | t1;
}
}
fail:
sreset();
//printf("-1");
MCUCR &= (0<<JTD);
MCUCR &= (0<<JTD);
return -1;
}
uint8_t sensirion::readStatus()
{
uint16_t _val;
// Command to send to the SHT1x to request Status
const uint8_t _gStatCmd = 0b00000111;
sendCommandSHT(_gStatCmd, _dataPin, _clockPin);
// result is immediate with read status.
//waitForResultSHT(_dataPin);
shtDelay(1);
_val = getData16SHT(_dataPin, _clockPin);
/*
// Send the required ack
digitalWrite(_dataPin, LOW);
pinMode(_dataPin, OUTPUT);
shtDelay(1);
digitalWrite(_clockPin, HIGH);
shtDelay(1);
digitalWrite(_clockPin, LOW);
shtDelay(1);
pinMode(_dataPin, INPUT);
*/
// end transmission, turn off gpio's
pinMode(_dataPin, INPUT);
pinMode(_clockPin, INPUT);
uint8_t rx_val = _val >> 8;
uint8_t rx_crc = _val & 0xff;
uint8_t local_crc = crc8add( 0, _gStatCmd );
local_crc = crc8add(local_crc, rx_val);
if (rx_crc != rev8bits(local_crc)){
Serial.println("SHT: crc error");
Serial.print(" Got: 0x"); Serial.println(rx_crc, HEX);
Serial.print(" Expected: 0x"); Serial.println(local_crc, HEX);
}
return rx_val;
}
