jeans/Tasmota
jeans/Tasmota
1
0
Fork 0
mirror of https://github.com/arendst/Tasmota.git synced 2025-08-01 15:07:42 +00:00
Code Issues Packages Projects Releases Wiki Activity

added some comments

Browse Source
This commit is contained in:
Markus Past 2018-12-30 12:47:59 +01:00
parent 1736409b18
commit 1e125fc4c6
1 changed files with 48 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
sonoff/xsns_39_max31855.ino
View File

@ -17,8 +17,6 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//#define USE_MAX31855
#ifdef USE_MAX31855
#define XSNS_39 39
@ -26,76 +24,96 @@
bool initialized = false;
struct MAX31855_ResultStruct{
uint8_t ErrorCode;
float ProbeTemperature;
float ReferenceTemperature;
uint8_t ErrorCode; // Error Codes: 0 = No Error / 1 = TC open circuit / 2 = TC short to GND / 4 = TC short to VCC
float ProbeTemperature; // Measured temperature of the 'hot' TC junction (probe temp)
float ReferenceTemperature; // Measured temperature of the 'cold' TC junction (reference temp)
} MAX31855_Result;
void MAX31855_Init(void){
if(initialized)
return;
// Set GPIO modes for SW-SPI
pinMode(pin[GPIO_MAX31855CS], OUTPUT);
pinMode(pin[GPIO_MAX31855CLK], OUTPUT);
pinMode(pin[GPIO_MAX31855DO], INPUT);
// Chip not selected / Clock low
digitalWrite(pin[GPIO_MAX31855CS], HIGH);
digitalWrite(pin[GPIO_MAX31855CLK], LOW);
initialized = true;
}
/*
* MAX31855_GetResult(void)
* Acquires the raw data via SPI, checks for MAX31855 errors and fills result structure
*/
void MAX31855_GetResult(void){
int32_t RawData = MAX31855_ShiftIn(32);
uint8_t probeerror = RawData & 0x7;
MAX31855_Result.ErrorCode = probeerror;
MAX31855_Result.ReferenceTemperature = MAX31855_GetReferenceTemperature(RawData);
if(probeerror)
MAX31855_Result.ProbeTemperature = NAN;
if(probeerror)
MAX31855_Result.ProbeTemperature = NAN; // Return NaN if MAX31855 reports an error
else
MAX31855_Result.ProbeTemperature = MAX31855_GetProbeTemperature(RawData);
}
/*
* MAX31855_GetProbeTemperature(int32_t RawData)
* Decodes and returns the temperature of TCs 'hot' junction from RawData
*/
float MAX31855_GetProbeTemperature(int32_t RawData){
if(RawData & 0x80000000)
RawData = (RawData >> 18) | 0xFFFFC000;
RawData = (RawData >> 18) | 0xFFFFC000; // Negative value - Drop lower 18 bits and extend to negative number
else
RawData >>= 18;
RawData >>= 18; // Positiv value - Drop lower 18 bits
float result = (RawData * 0.25);
float result = (RawData * 0.25); // MAX31855 LSB resolution is 0.25°C for probe temperature
return (Settings.flag.temperature_conversion) ? ConvertTemp(result) : result;
return (Settings.flag.temperature_conversion) ? ConvertTemp(result) : result; // Check if we have to convert to Fahrenheit
}
/*
* MAX31855_GetReferenceTemperature(int32_t RawData)
* Decodes and returns the temperature of TCs 'cold' junction from RawData
*/
float MAX31855_GetReferenceTemperature(int32_t RawData){
if(RawData & 0x8000)
RawData = (RawData >> 4) | 0xFFFFF000;
RawData = (RawData >> 4) | 0xFFFFF000; // Negative value - Drop lower 4 bits and extend to negative number
else
RawData = (RawData >> 4) & 0x00000FFF;
RawData = (RawData >> 4) & 0x00000FFF; // Positiv value - Drop lower 4 bits and mask out remaining bits (probe temp, error bit, etc.)
float result = (RawData * 0.0625);
float result = (RawData * 0.0625); // MAX31855 LSB resolution is 0.0625°C for reference temperature
return (Settings.flag.temperature_conversion) ? ConvertTemp(result) : result;
return (Settings.flag.temperature_conversion) ? ConvertTemp(result) : result; // Check if we have to convert to Fahrenheit
}
/*
* MAX31855_ShiftIn(uint8_t Length)
* Communicates with MAX31855 via SW-SPI and returns the raw data read from the chip
*/
int32_t MAX31855_ShiftIn(uint8_t Length){
int32_t dataIn = 0;
digitalWrite(pin[GPIO_MAX31855CS], LOW);
delayMicroseconds(1);
digitalWrite(pin[GPIO_MAX31855CS], LOW); // CS = LOW -> Start SPI communication
delayMicroseconds(1); // CS fall to output enable = max. 100ns
for(uint8_t i = 0; i < Length; i++)
{
digitalWrite(pin[GPIO_MAX31855CLK], LOW);
delayMicroseconds(1);
delayMicroseconds(1); // CLK pulse width low = min. 100ns / CLK fall to output valid = max. 40ns
dataIn <<= 1;
if(digitalRead(pin[GPIO_MAX31855DO]))
dataIn |= 1;
digitalWrite(pin[GPIO_MAX31855CLK], HIGH);
delayMicroseconds(1);
delayMicroseconds(1); // CLK pulse width high = min. 100ns
}
digitalWrite(pin[GPIO_MAX31855CS], HIGH);
digitalWrite(pin[GPIO_MAX31855CS], HIGH); // CS = HIGH -> End SPI communication
digitalWrite(pin[GPIO_MAX31855CLK], LOW);
return dataIn;
}
@ -109,6 +127,16 @@ void MAX31855_Show(bool Json){
if(Json){
snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"%s\":{\"" D_JSON_PROBETEMPERATURE "\":%s,\"" D_JSON_REFERENCETEMPERATURE "\":%s,\"" D_JSON_ERROR "\":%d}"), \
mqtt_data, "MAX31855", probetemp, referencetemp, MAX31855_Result.ErrorCode);
#ifdef USE_DOMOTICZ
if (0 == tele_period) {
DomoticzSensor(DZ_TEMP, probetemp);
}
#endif // USE_DOMOTICZ
#ifdef USE_KNX
if (0 == tele_period) {
KnxSensor(KNX_TEMPERATURE, MAX31855_Result.ProbeTemperature);
}
#endif // USE_KNX
} else {
#ifdef USE_WEBSERVER
snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_TEMP, mqtt_data, "MAX31855", probetemp, TempUnit());
@ -116,20 +144,6 @@ void MAX31855_Show(bool Json){
}
}
// void MAX31855_ShowDebug(void){
// char probetemp[33];
// char referencetemp[33];
// dtostrfd(MAX31855_Result.ProbeTemperature, Settings.flag2.temperature_resolution, probetemp);
// dtostrfd(MAX31855_Result.ReferenceTemperature, Settings.flag2.temperature_resolution, referencetemp);
// snprintf_P(mqtt_data, sizeof(mqtt_data), "%s %d %s %d %s %d %s %d %s %d %s %s %s %s %s %d", \
// "CS:", pin[GPIO_MAX31855CS], "CLK:", pin[GPIO_MAX31855CLK], "DO:", pin[GPIO_MAX31855DO], \
// "DO-State:", digitalRead(pin[GPIO_MAX31855DO]), \
// "RAW-Data:", MAX31855_ShiftIn(32), \
// "Probe-Temp:", probetemp, "Internal-Temp:", referencetemp, "Error:", MAX31855_Result.ErrorCode);
// }
/*********************************************************************************************\
* Interface
\*********************************************************************************************/
@ -147,7 +161,6 @@ boolean Xsns39(byte function)
MAX31855_GetResult();
break;
case FUNC_JSON_APPEND:
//MAX31855_ShowDebug();
MAX31855_Show(true);
break;
#ifdef USE_WEBSERVER