Added possibility to use other SPI device

src/MAX31855.cpp

@@ -14,7 +14,7 @@
      near the converter because this may produce an errors.
    - It is strongly recommended to add a 10nF/0.01mF ceramic surface-mount capacitor, placed across
      the T+ and T- pins, to filter noise on the thermocouple lines.
-     
+
    written by : enjoyneering79
    sourse code: https://github.com/enjoyneering/MAX31855
 
@@ -68,12 +68,13 @@ MAX31855::MAX31855(uint8_t cs)
     Initializes & configures hardware SPI
 */
 /**************************************************************************/
-void MAX31855::begin(void)
+void MAX31855::begin(SPIClass *SPI_pointer)
 {
   pinMode(_cs, OUTPUT);
   digitalWrite(_cs, HIGH);                  //disables SPI interface for MAX31855, but it will initiate measurement/conversion
 
-  SPI.begin();                              //setting hardware SCK, MOSI, SS to output, pull SCK, MOSI low & SS high    
+  MAXSPI = SPI_pointer;
+  MAXSPI->begin();                              //setting hardware SCK, MOSI, SS to output, pull SCK, MOSI low & SS high
 
   delay(MAX31855_CONVERSION_POWER_UP_TIME);
 }
@@ -231,18 +232,18 @@ int32_t MAX31855::readRawData(void)
 
   delay(MAX31855_CONVERSION_TIME);
 
-  SPI.beginTransaction(SPISettings(5000000, MSBFIRST, SPI_MODE0)); //up to 5MHz, read MSB first, SPI mode 0, see note
+  MAXSPI->beginTransaction(SPISettings(500000, MSBFIRST, SPI_MODE0)); //up to 5MHz, read MSB first, SPI mode 0, see note
 
   digitalWrite(_cs, LOW);                                          //set software CS low to enable SPI interface for MAX31855
 
   for (uint8_t i = 0; i < 2; i++)                                  //read 32-bits via hardware SPI, in order MSB->LSB (D31..D0 bit)
   {
-    rawData = (rawData << 16) | SPI.transfer16(0x0000);            //chip has read only SPI & MOSI not connected, so it doesn't metter what to send
+    rawData = (rawData << 16) | MAXSPI->transfer16(0x0000);            //chip has read only SPI & MOSI not connected, so it doesn't metter what to send
   }
 
   digitalWrite(_cs, HIGH);                                         //disables SPI interface for MAX31855, but it will initiate measurement/conversion
 
-  SPI.endTransaction();                                            //de-asserting hardware CS & free hw SPI for other slaves
+  MAXSPI->endTransaction();                                            //de-asserting hardware CS & free hw SPI for other slaves
 
   return rawData;
 }

src/MAX31855.h

@@ -14,7 +14,7 @@
      near the converter because this may produce an errors.
    - It is strongly recommended to add a 10nF/0.01mF ceramic surface-mount capacitor, placed across
      the T+ and T- pins, to filter noise on the thermocouple lines.
-     
+
    written by : enjoyneering79
    sourse code: https://github.com/enjoyneering/MAX31855
 
@@ -60,9 +60,7 @@
 #include <avr/pgmspace.h>                  //use for PROGMEM Arduino STM32
 #endif
 
-#ifndef  MAX31855_SOFT_SPI                 //enable upload hw driver spi.h
 #include <SPI.h>
-#endif
 
 
 #define MAX31855_CONVERSION_POWER_UP_TIME   200    //in milliseconds
@@ -87,15 +85,15 @@ class MAX31855
   public:
    MAX31855(uint8_t cs);
 
-           void     begin(void);
+           void     begin(SPIClass *SPI_pointer = &SPI);
            uint8_t  detectThermocouple(int32_t rawValue = MAX31855_FORCE_READ_DATA);
            uint16_t getChipID(int32_t rawValue = MAX31855_FORCE_READ_DATA);
            float    getTemperature(int32_t rawValue = MAX31855_FORCE_READ_DATA);
            float    getColdJunctionTemperature(int32_t rawValue = MAX31855_FORCE_READ_DATA);
    virtual int32_t  readRawData(void);
-
-  private:
 
+  private:
+   SPIClass * MAXSPI = NULL;
   protected:
    uint8_t _cs;
 };