MAX31855 driver for Sonoff-Tasmota - Initial commit

sonoff/i18n.h

@@ -106,8 +106,10 @@
 #define D_JSON_PRESSURE "Pressure"
 #define D_JSON_PRESSUREATSEALEVEL "SeaPressure"
 #define D_JSON_PRESSURE_UNIT "PressureUnit"
+#define D_JSON_PROBETEMPERATURE "ProbeTemperature"
 #define D_JSON_PROGRAMFLASHSIZE "ProgramFlashSize"
 #define D_JSON_PROGRAMSIZE "ProgramSize"
+#define D_JSON_REFERENCETEMPERATURE "ReferenceTemperature"
 #define D_JSON_RESET "Reset"
 #define D_JSON_RESTARTING "Restarting"
 #define D_JSON_RESTARTREASON "RestartReason"

sonoff/language/en-GB.h

@@ -540,6 +540,9 @@
 #define D_SENSOR_RF_SENSOR "RF Sensor"
 #define D_SENSOR_AZ_RX   "AZ Rx"
 #define D_SENSOR_AZ_TX   "AZ Tx"
+#define D_SENSOR_MAX31855_CS  "MAX31855 CS"
+#define D_SENSOR_MAX31855_CLK "MAX31855 CLK"
+#define D_SENSOR_MAX31855_DO  "MAX31855 DO"
 
 // Units
 #define D_UNIT_AMPERE "A"

sonoff/my_user_config.h

@@ -285,6 +285,9 @@
 //  #define W1_PARASITE_POWER                      // If using USE_DS18x20 then optimize for parasite powered sensors
 //  #define DS18B20_INTERNAL_PULLUP	               // Use INPUT_PULLUP internal pullup resistors for single DS18B20
 
+// -- SPI sensors ----------------------------------
+#define USE_MAX31855                           // Enable MAX31855 K-Type thermocouple sensor
+
 // -- I2C sensors ---------------------------------
 #define USE_I2C                                  // I2C using library wire (+10k code, 0k2 mem, 124 iram)
 

sonoff/sonoff_template.h

@@ -143,6 +143,9 @@ enum UserSelectablePins {
   GPIO_RF_SENSOR,      // Rf receiver with sensor decoding
   GPIO_AZ_TXD,         // AZ-Instrument 7798 Serial interface
   GPIO_AZ_RXD,         // AZ-Instrument 7798 Serial interface
+  GPIO_MAX31855CS,     // MAX31855 Serial interface
+  GPIO_MAX31855CLK,    // MAX31855 Serial interface
+  GPIO_MAX31855DO,     // MAX31855 Serial interface
   GPIO_SENSOR_END };
 
 // Programmer selectable GPIO functionality offset by user selectable GPIOs
@@ -204,7 +207,8 @@ const char kSensorNames[] PROGMEM =
   D_SENSOR_MGC3130_XFER "|" D_SENSOR_MGC3130_RESET "|"
   D_SENSOR_SSPI_MISO "|" D_SENSOR_SSPI_MOSI "|" D_SENSOR_SSPI_SCLK "|" D_SENSOR_SSPI_CS "|" D_SENSOR_SSPI_DC "|"
   D_SENSOR_RF_SENSOR "|"
-  D_SENSOR_AZ_TX "|" D_SENSOR_AZ_RX;
+  D_SENSOR_AZ_TX "|" D_SENSOR_AZ_RX "|"
+  D_SENSOR_MAX31855_CS "|" D_SENSOR_MAX31855_CLK "|" D_SENSOR_MAX31855_DO;
 
 /********************************************************************************************/
 
@@ -461,6 +465,11 @@ const uint8_t kGpioNiceList[] PROGMEM = {
   GPIO_AZ_TXD,         // AZ-Instrument 7798 CO2 datalogger Serial interface
   GPIO_AZ_RXD          // AZ-Instrument 7798 CO2 datalogger Serial interface
 #endif
+#ifdef USE_MAX31855
+  GPIO_MAX31855CS,   // MAX31855 Serial interface
+  GPIO_MAX31855CLK,  // MAX31855 Serial interface
+  GPIO_MAX31855DO,   // MAX31855 Serial interface    
+#endif
 };
 
 const uint8_t kModuleNiceList[MAXMODULE] PROGMEM = {

sonoff/xsns_39_max31855.ino

@@ -0,0 +1,163 @@
+/*
+  xsns_39_max31855.ino - MAX31855 thermocouple sensor support for Sonoff-Tasmota
+
+  Copyright (C) 2018  Markus Past
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+//#define USE_MAX31855
+
+#ifdef USE_MAX31855
+
+#define XSNS_39              39
+
+bool initialized = false;
+
+struct MAX31855_ResultStruct{
+    uint8_t ErrorCode;
+    float ProbeTemperature;
+    float ReferenceTemperature;
+} MAX31855_Result;
+
+void MAX31855_Init(void){
+    if(initialized)
+        return;
+
+    pinMode(pin[GPIO_MAX31855CS], OUTPUT);
+    pinMode(pin[GPIO_MAX31855CLK], OUTPUT);
+    pinMode(pin[GPIO_MAX31855DO], INPUT);
+    digitalWrite(pin[GPIO_MAX31855CS], HIGH);
+    digitalWrite(pin[GPIO_MAX31855CLK], LOW);
+
+    initialized = true;
+}
+
+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;
+    else
+        MAX31855_Result.ProbeTemperature = MAX31855_GetProbeTemperature(RawData);
+}
+
+float MAX31855_GetProbeTemperature(int32_t RawData){
+    if(RawData & 0x80000000)
+        RawData = (RawData >> 18) | 0xFFFFC000;
+    else
+        RawData >>= 18;
+
+    float result = (RawData * 0.25);
+
+    return (Settings.flag.temperature_conversion) ? ConvertTemp(result) : result;
+}
+
+float MAX31855_GetReferenceTemperature(int32_t RawData){
+    if(RawData & 0x8000)
+        RawData = (RawData >> 4) | 0xFFFFF000;
+    else
+        RawData = (RawData >> 4) & 0x00000FFF;
+
+    float result = (RawData * 0.0625);
+
+    return (Settings.flag.temperature_conversion) ? ConvertTemp(result) : result;
+}
+
+int32_t MAX31855_ShiftIn(uint8_t Length){
+    int32_t dataIn = 0;
+
+    digitalWrite(pin[GPIO_MAX31855CS], LOW);
+    delayMicroseconds(1);
+    
+    for(uint8_t i = 0; i < Length; i++)
+    {
+        digitalWrite(pin[GPIO_MAX31855CLK], LOW);
+        delayMicroseconds(1);
+        dataIn <<= 1;
+        if(digitalRead(pin[GPIO_MAX31855DO]))
+            dataIn |= 1;
+        digitalWrite(pin[GPIO_MAX31855CLK], HIGH);
+        delayMicroseconds(1);
+    }
+
+    digitalWrite(pin[GPIO_MAX31855CS], HIGH);
+    digitalWrite(pin[GPIO_MAX31855CLK], LOW);
+    return dataIn;    
+}
+
+void MAX31855_Show(bool Json){
+    char probetemp[33];
+    char referencetemp[33];
+    dtostrfd(MAX31855_Result.ProbeTemperature, Settings.flag2.temperature_resolution, probetemp);
+    dtostrfd(MAX31855_Result.ReferenceTemperature, Settings.flag2.temperature_resolution, referencetemp);
+
+    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);
+    } else {
+#ifdef USE_WEBSERVER
+        snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_TEMP, mqtt_data, "MAX31855", probetemp, TempUnit());
+#endif  // USE_WEBSERVER
+    }
+}
+
+
+// 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
+\*********************************************************************************************/
+
+boolean Xsns39(byte function)
+{
+  boolean result = false;
+  if((pin[GPIO_MAX31855CS] < 99) && (pin[GPIO_MAX31855CLK] < 99) && (pin[GPIO_MAX31855DO] < 99)){
+
+    switch (function) {
+      case FUNC_INIT:
+        MAX31855_Init();
+        break;
+      case FUNC_EVERY_SECOND:
+        MAX31855_GetResult();
+        break;
+      case FUNC_JSON_APPEND:
+        //MAX31855_ShowDebug();
+        MAX31855_Show(true);
+        break;
+#ifdef USE_WEBSERVER
+      case FUNC_WEB_APPEND:
+        MAX31855_Show(false);
+        break;
+#endif  // USE_WEBSERVER
+    }
+  }
+  return result;
+}
+
+#endif  // USE_MAX31855