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Merge pull request #2 from RobTillaart/issue16
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+ check return value wire.reset() in readScratchPad
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@RobTillaart
RobTillaart committed Jul 4, 2015
2 parents ad90160 + db51996 commit dd0cc6a
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Showing 2 changed files with 235 additions and 269 deletions.
104 changes: 35 additions & 69 deletions DallasTemperature.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ DallasTemperature::DallasTemperature() {}
DallasTemperature::DallasTemperature(OneWire* _oneWire)

#if REQUIRESALARMS
: _AlarmHandler(&defaultAlarmHandler)
: _AlarmHandler(&defaultAlarmHandler)
#endif
{
setOneWire(_oneWire);
Expand Down Expand Up @@ -101,19 +101,22 @@ bool DallasTemperature::isConnected(const uint8_t* deviceAddress)
// also allows for updating the read scratchpad
bool DallasTemperature::isConnected(const uint8_t* deviceAddress, uint8_t* scratchPad)
{
readScratchPad(deviceAddress, scratchPad);
return (_wire->crc8(scratchPad, 8) == scratchPad[SCRATCHPAD_CRC]);
bool b = readScratchPad(deviceAddress, scratchPad);
return b && (_wire->crc8(scratchPad, 8) == scratchPad[SCRATCHPAD_CRC]);
}

// read device's scratch pad
void DallasTemperature::readScratchPad(const uint8_t* deviceAddress, uint8_t* scratchPad)
// returns false if it fails to reset the Wire bus
bool DallasTemperature::readScratchPad(const uint8_t* deviceAddress, uint8_t* scratchPad)
{
// send the command
_wire->reset();
// send the reset command and fail fast
int b = _wire->reset();
if (b == 0) return false;

_wire->select(deviceAddress);
_wire->write(READSCRATCH);

// TODO => collect all comments & use simple loop
// Read all registers in a simple loop
// byte 0: temperature LSB
// byte 1: temperature MSB
// byte 2: high alarm temp
Expand All @@ -126,53 +129,16 @@ void DallasTemperature::readScratchPad(const uint8_t* deviceAddress, uint8_t* sc
// byte 7: DS18S20: COUNT_PER_C
// DS18B20 & DS1822: store for crc
// byte 8: SCRATCHPAD_CRC
//
// for(int i=0; i<9; i++)
// {
// scratchPad[i] = _wire->read();
// }


// read the response

// byte 0: temperature LSB
scratchPad[TEMP_LSB] = _wire->read();

// byte 1: temperature MSB
scratchPad[TEMP_MSB] = _wire->read();

// byte 2: high alarm temp
scratchPad[HIGH_ALARM_TEMP] = _wire->read();

// byte 3: low alarm temp
scratchPad[LOW_ALARM_TEMP] = _wire->read();

// byte 4:
// DS18S20: store for crc
// DS18B20 & DS1822: configuration register
scratchPad[CONFIGURATION] = _wire->read();

// byte 5:
// internal use & crc
scratchPad[INTERNAL_BYTE] = _wire->read();

// byte 6:
// DS18S20: COUNT_REMAIN
// DS18B20 & DS1822: store for crc
scratchPad[COUNT_REMAIN] = _wire->read();

// byte 7:
// DS18S20: COUNT_PER_C
// DS18B20 & DS1822: store for crc
scratchPad[COUNT_PER_C] = _wire->read();

// byte 8:
// SCTRACHPAD_CRC
scratchPad[SCRATCHPAD_CRC] = _wire->read();
for(uint8_t i = 0; i < 9; i++)
{
scratchPad[i] = _wire->read();
}

_wire->reset();
b = _wire->reset();
return (b == 1);
}


// writes device's scratch pad
void DallasTemperature::writeScratchPad(const uint8_t* deviceAddress, const uint8_t* scratchPad)
{
Expand All @@ -187,7 +153,7 @@ void DallasTemperature::writeScratchPad(const uint8_t* deviceAddress, const uint
_wire->select(deviceAddress); //<--this line was missing
// save the newly written values to eeprom
_wire->write(COPYSCRATCH, parasite);
delay(20); // <--- added 20ms delay to allow 10ms long EEPROM write operation (as specified by datasheet)
delay(20); // <--- added 20ms delay to allow 10ms long EEPROM write operation (as specified by datasheet)
if (parasite) delay(10); // 10ms delay
_wire->reset();
}
Expand Down Expand Up @@ -402,7 +368,7 @@ float DallasTemperature::getTempCByIndex(uint8_t deviceIndex)
{
DeviceAddress deviceAddress;
if (!getAddress(deviceAddress, deviceIndex))
return DEVICE_DISCONNECTED_C;
return DEVICE_DISCONNECTED_C;
return getTempC((uint8_t*)deviceAddress);
}

Expand All @@ -411,16 +377,16 @@ float DallasTemperature::getTempFByIndex(uint8_t deviceIndex)
{
DeviceAddress deviceAddress;
if (!getAddress(deviceAddress, deviceIndex))
return DEVICE_DISCONNECTED_F;
return DEVICE_DISCONNECTED_F;
return getTempF((uint8_t*)deviceAddress);
}

// reads scratchpad and returns fixed-point temperature, scaling factor 2^-7
int16_t DallasTemperature::calculateTemperature(const uint8_t* deviceAddress, uint8_t* scratchPad)
{
int16_t fpTemperature =
(((int16_t) scratchPad[TEMP_MSB]) << 11) |
(((int16_t) scratchPad[TEMP_LSB]) << 3);
(((int16_t) scratchPad[TEMP_MSB]) << 11) |
(((int16_t) scratchPad[TEMP_LSB]) << 3);

/*
DS1820 and DS18S20 have a 9-bit temperature register.
Expand Down Expand Up @@ -448,11 +414,11 @@ int16_t DallasTemperature::calculateTemperature(const uint8_t* deviceAddress, ui
*/

if (deviceAddress[0] == DS18S20MODEL)
fpTemperature = ((fpTemperature & 0xfff0) << 3) - 16 +
(
((scratchPad[COUNT_PER_C] - scratchPad[COUNT_REMAIN]) << 7) /
scratchPad[COUNT_PER_C]
);
fpTemperature = ((fpTemperature & 0xfff0) << 3) - 16 +
(
((scratchPad[COUNT_PER_C] - scratchPad[COUNT_REMAIN]) << 7) /
scratchPad[COUNT_PER_C]
);

return fpTemperature;
}
Expand Down Expand Up @@ -505,7 +471,7 @@ bool DallasTemperature::isParasitePowerMode(void)
TH and TL Register Format
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
S 2^6 2^5 2^4 2^3 2^2 2^1 2^0
S 2^6 2^5 2^4 2^3 2^2 2^1 2^0
Only bits 11 through 4 of the temperature register are used
in the TH and TL comparison since TH and TL are 8-bit
Expand Down Expand Up @@ -576,7 +542,7 @@ void DallasTemperature::resetAlarmSearch()
alarmSearchJunction = -1;
alarmSearchExhausted = 0;
for(uint8_t i = 0; i < 7; i++)
alarmSearchAddress[i] = 0;
alarmSearchAddress[i] = 0;
}

// This is a modified version of the OneWire::search method.
Expand Down Expand Up @@ -693,7 +659,7 @@ void DallasTemperature::processAlarms(void)
while (alarmSearch(alarmAddr))
{
if (validAddress(alarmAddr))
_AlarmHandler(alarmAddr);
_AlarmHandler(alarmAddr);
}
}

Expand All @@ -710,11 +676,11 @@ void DallasTemperature::defaultAlarmHandler(const uint8_t* deviceAddress)

#endif

// IF alarm is not used one can store a 16 bit int of userdata in the alarm
// IF alarm is not used one can store a 16 bit int of userdata in the alarm
// registers. E.g. an ID of the sensor.
// See github issue #29

// note if device is not connected it will fail writing the data.
// note if device is not connected it will fail writing the data.
void DallasTemperature::setUserData(const uint8_t* deviceAddress, int16_t data)
{
ScratchPad scratchPad;
Expand All @@ -730,7 +696,7 @@ int16_t DallasTemperature::getUserData(const uint8_t* deviceAddress)
{
int16_t data = 0;
ScratchPad scratchPad;
if (isConnected(deviceAddress, scratchPad))
if (isConnected(deviceAddress, scratchPad))
{
data = scratchPad[HIGH_ALARM_TEMP] << 8;
data += scratchPad[LOW_ALARM_TEMP];
Expand Down Expand Up @@ -770,7 +736,7 @@ float DallasTemperature::toCelsius(float fahrenheit)
float DallasTemperature::rawToCelsius(int16_t raw)
{
if (raw <= DEVICE_DISCONNECTED_RAW)
return DEVICE_DISCONNECTED_C;
return DEVICE_DISCONNECTED_C;
// C = RAW/128
return (float)raw * 0.0078125;
}
Expand All @@ -779,7 +745,7 @@ float DallasTemperature::rawToCelsius(int16_t raw)
float DallasTemperature::rawToFahrenheit(int16_t raw)
{
if (raw <= DEVICE_DISCONNECTED_RAW)
return DEVICE_DISCONNECTED_F;
return DEVICE_DISCONNECTED_F;
// C = RAW/128
// F = (C*1.8)+32 = (RAW/128*1.8)+32 = (RAW*0.0140625)+32
return ((float)raw * 0.0140625) + 32;
Expand Down
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