Merge pull request #28 from leonardocavagnis/tc_pin_fix

Fix NaN readings issue in thermocouple `TCTempProbeClass` class

Author: leonardocavagnis

src/TCTempProbeClass.cpp

@@ -18,8 +18,9 @@ uint8_t* boardInfo();
 TCTempProbeClass::TCTempProbeClass(PinName tc_cs_pin,
                                      PinName ch_sel0_pin, 
                                      PinName ch_sel1_pin,
-                                     PinName ch_sel2_pin)
-: MAX31855Class(tc_cs_pin), _tc_cs{tc_cs_pin}, _ch_sel0{ch_sel0_pin}, _ch_sel1{ch_sel1_pin}, _ch_sel2{ch_sel2_pin}                  
+                                     PinName ch_sel2_pin,
+                                     PinName tc_th_pin)
+: MAX31855Class(tc_cs_pin), _tc_cs{tc_cs_pin}, _ch_sel0{ch_sel0_pin}, _ch_sel1{ch_sel1_pin}, _ch_sel2{ch_sel2_pin}, _tc_th{tc_th_pin}                  
 { }
 
 TCTempProbeClass::~TCTempProbeClass() 
@@ -31,6 +32,7 @@ bool TCTempProbeClass::begin() {
     pinMode(_ch_sel0, OUTPUT);
     pinMode(_ch_sel1, OUTPUT);
     pinMode(_ch_sel2, OUTPUT);
+    pinMode(_tc_th, OUTPUT);
 
     pinMode(_tc_cs, OUTPUT);
 
@@ -92,10 +94,12 @@ void TCTempProbeClass::end() {
 
 void TCTempProbeClass::_enable() {
     digitalWrite(_tc_cs, LOW);
+    digitalWrite(_tc_th, LOW);
 }
 
 void TCTempProbeClass::_disable() {
     digitalWrite(_tc_cs, HIGH);
+    digitalWrite(_tc_th, HIGH);
 }
 
 TCTempProbeClass MachineControl_TCTempProbe;

src/TCTempProbeClass.h

@@ -41,7 +41,8 @@ class TCTempProbeClass: public MAX31855Class {
     TCTempProbeClass(PinName tc_cs_pin = MC_TC_CS_PIN, 
                      PinName ch_sel0_pin = MC_TC_SEL0_PIN, 
                      PinName ch_sel1_pin = MC_TC_SEL1_PIN, 
-                     PinName ch_sel2_pin = MC_TC_SEL2_PIN);
+                     PinName ch_sel2_pin = MC_TC_SEL2_PIN,
+                     PinName tc_th_pin = MC_TC_TH_PIN);
 
     /**
      * @brief Destruct the TCTempProbeClass object.
@@ -74,6 +75,7 @@ class TCTempProbeClass: public MAX31855Class {
     PinName _ch_sel0;   // Pin for the first channel selection bit
     PinName _ch_sel1;   // Pin for the second channel selection bit
     PinName _ch_sel2;   // Pin for the third channel selection bit
+    PinName _tc_th;     // Pin for the TC/RTD connection
 
     /**
      * @brief Enable the chip select (CS) of the MAX31855 digital converter.

src/pins_mc.h

@@ -84,6 +84,7 @@
 #define MC_TC_SEL0_PIN      MC_RTD_SEL0_PIN
 #define MC_TC_SEL1_PIN      MC_RTD_SEL1_PIN
 #define MC_TC_SEL2_PIN      MC_RTD_SEL2_PIN
+#define MC_TC_TH_PIN        MC_RTD_TH_PIN
 
 /* USB */
 #define MC_USB_PWR_PIN      PB_14