Diff: max31855.cpp

Revision:

2:2613cf295ccb

Parent:

1:5eeee89cb281

Child:

3:e2731f1e595b

--- a/max31855.cpp	Tue Oct 23 10:51:21 2012 +0000
+++ b/max31855.cpp	Wed Jan 06 15:49:29 2016 +0000
@@ -1,102 +1,80 @@
-
 #include <mbed.h>
 #include "max31855.h"
 
-max31855::max31855(SPI& _spi, PinName _ncs) : spi(_spi), ncs(_ncs) {
+max31855::max31855(SPI& _spi, PinName ncs1, PinName ncs2) : _spi(_spi), _CS_1(ncs1), _CS_2(ncs2)
+{
 
 }
 
-float max31855::read_temp() {
+float max31855::read_temp(max31855::THERMOCOUPLES thermo)
+{
     short value = 0;
     float temp = 0;
-    
     //Variables to hold probe temperature
     uint8_t tempProbeHigh=0;
     uint8_t tempProbeLow=0;
-    
     //Variables to hold chip temperature and device status
     uint8_t tempChipHigh=0;
     uint8_t tempChipLow=0;
-    
-    if (pollTimer.read_ms() > 250){
+    if (_pollTimer.read_ms() > 250) {
         //Set CS to initiate transfer and stop conversion
-        select();
-    
+        select(thermo);
         //Read in Probe tempeature
-        tempProbeHigh = spi.write(0);
-        tempProbeLow = spi.write(0);
-        
+        tempProbeHigh = _spi.write(0);
+        tempProbeLow = _spi.write(0);
         //Get the chip temperature and the fault data
-        tempChipHigh = spi.write(0);
-        tempChipLow = spi.write(0);
-        
-        //Set the chip temperature    
-        chipTemp = (tempChipHigh<<4 | tempChipLow>>4)*0.25;
-        
+        tempChipHigh = _spi.write(0);
+        tempChipLow = _spi.write(0);
+        //Set the chip temperature
+        _chipTemp = (tempChipHigh<<4 | tempChipLow>>4)*0.0625;
         //Set CS to stop transfer and restart conversion
-        deselect(); 
-        
-        //Check for a fault (last bit of transfer is fault bit)
-        if ((tempProbeLow & 1)==1){
-            //Chip reports a fault, extract fault from Chip Temperature data
-            int faultType = (tempChipLow & 7);
-            
-            faultCode=faultType;
-            
-            return 2000+faultType;
-            /*if (faultType==1){
-                //Open circuit (no TC)
-                return 2000 + faultType;
-            }else if (faultType==2){
-                //Short to GND
-                return 2000 + faultType;
-            }else if (faultType==4){
-                //Short to VCC               
-                return 0.4;
-            }else{
-                return 0.5;
-            }*/
-        }else{
+        deselect(thermo);
+        if (CHECK_BIT(tempProbeLow, 0)) {
+            //not connected error
+            if(CHECK_BIT(tempChipLow, 0))return -2;
+            //short to ground
+            else if(CHECK_BIT(tempChipLow, 1))return -3;
+            //short to VCC
+            else if(CHECK_BIT(tempChipLow, 2))return -4;
+            else return -5;
+        } else {
             //Integer value of temperature
             value = (tempProbeHigh<< 6 | tempProbeLow>>2);
-    
             //Get actual temperature (last 2 bits of integer are decimal 0.5 and 0.25)
             temp = (value*0.25); // Multiply the value by 0.25 to get temp in C or
-                             //  * (9.0/5.0)) + 32.0;   // Convert value to F (ensure proper floats!)
-                             
+            //  * (9.0/5.0)) + 32.0;   // Convert value to F (ensure proper floats!)
             return temp;
         }
-    }else{
-        //Chip not ready for reading
-        return -1;
+    } else {
+        return 8;
     }
 }
 
-void max31855::select() {
+void max31855::select(THERMOCOUPLES thermo)
+{
     //Set CS low to start transmission (interrupts conversion)
-    ncs = 0;
-}
-
-void max31855::deselect() {
-    //Set CS high to stop transmission (restarts conversion)
-    ncs = 1;
-    //Reset conversion timer
-    pollTimer.reset();
+    if(thermo == THERMO_1) _CS_1 = 0;
+    else _CS_2 = 0;
 }
 
-void max31855::initialise(int setType) {
-    //Start the conversion timer
-    pollTimer.start();
-    faultCode=0;
+void max31855::deselect(THERMOCOUPLES thermo)
+{
+    //Set CS high to stop transmission (restarts conversion)
+    if(thermo == THERMO_1) _CS_1 = 1;
+    else _CS_2 = 1;
+    _pollTimer.reset();
 }
 
-int max31855::ready() {
+void max31855::initialise(int setType)
+{
+    //Start the conversion timer
+    _pollTimer.start();
+    _faultCode=0;
+}
+
+int max31855::ready()
+{
     //Check to see if conversion is complete
-    if (pollTimer.read_ms() > 250) {
-        //Conversion complete
-        return 1;
-    }else{
-        //Conversion incomplete
-        return 0;
-    }
+    if(_pollTimer.read_ms() > 500 ) return 1;
+    else return 0;
 }
\ No newline at end of file