Revision 1:5eeee89cb281, committed 2012-10-23

Comitter:

Stavlin

Date:

Tue Oct 23 10:51:21 2012 +0000

Parent:

0:656c522152d4

Commit message:

Fixed fault reporting. Returns a value of 2000 + fault code on error.

Changed in this revision

--- a/max31855.cpp	Thu Aug 16 12:46:52 2012 +0000
+++ b/max31855.cpp	Tue Oct 23 10:51:21 2012 +0000
@@ -1,98 +1,102 @@
-
-#include <mbed.h>
-#include "max31855.h"
-
-max31855::max31855(SPI& _spi, PinName _ncs) : spi(_spi), ncs(_ncs) {
-
-}
-
-float max31855::read_temp() {
-    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){
-        //Set CS to initiate transfer and stop conversion
-        select();
-    
-        //Read in Probe tempeature
-        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;
-        
-        //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);
-            
-            if (faultType==1){
-                //Open circuit (no TC)
-                return 0.1;
-            }else if (faultType==2){
-                //Short to GND
-                return 0.2;
-            }else if (faultType==4){
-                //Short to VCC               
-                return 0.4;
-            }else{
-                return 0.5;
-            }
-        }else{
-            //Set CS to stop transfer and restart conversion
-            deselect();    
-    
-            //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!)
-                             
-            return temp;
-        }
-    }else{
-        //Chip not ready for reading
-        return -1;
-    }
-}
-
-void max31855::select() {
-    //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();
-}
-
-void max31855::initialise() {
-    //Start the conversion timer
-    pollTimer.start();
-}
-
-int max31855::ready() {
-    //Check to see if conversion is complete
-    if (pollTimer.read_ms() > 250) {
-        //Conversion complete
-        return 1;
-    }else{
-        //Conversion incomplete
-        return 0;
-    }
+
+#include <mbed.h>
+#include "max31855.h"
+
+max31855::max31855(SPI& _spi, PinName _ncs) : spi(_spi), ncs(_ncs) {
+
+}
+
+float max31855::read_temp() {
+    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){
+        //Set CS to initiate transfer and stop conversion
+        select();
+    
+        //Read in Probe tempeature
+        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;
+        
+        //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{
+            //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!)
+                             
+            return temp;
+        }
+    }else{
+        //Chip not ready for reading
+        return -1;
+    }
+}
+
+void max31855::select() {
+    //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();
+}
+
+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;
+    }
 }
\ No newline at end of file

--- a/max31855.h	Thu Aug 16 12:46:52 2012 +0000
+++ b/max31855.h	Tue Oct 23 10:51:21 2012 +0000
@@ -13,9 +13,10 @@
     max31855(SPI& _spi, PinName _ncs);
     void select();
     void deselect();
-    void initialise();
+    void initialise(int setType=0);
     
     int ready();
+    int faultCode;
     
     float chipTemp;
     float read_temp();