Revision 0:33fb492d139e, committed 2020-06-08

Comitter:

cristian_junca

Date:

Mon Jun 08 23:18:38 2020 +0000

Commit message:

Read temperatura with SPI communication

Changed in this revision

diff -r 000000000000 -r 33fb492d139e max6675.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/max6675.cpp	Mon Jun 08 23:18:38 2020 +0000
@@ -0,0 +1,40 @@
+#include "mbed.h"
+#include "max6675.h"
+ 
+max6675::max6675(SPI& _spi, PinName _ss) : spi(_spi), ss(_ss) {
+ 
+}
+ 
+float max6675::read_temp() {
+    short value = 0;
+    float temp = 0;
+    
+    uint8_t highByte=0;
+    uint8_t lowByte=0;
+    
+    select();
+    wait(.25); //This delay is needed else it doesn't seem to update the temp
+ 
+    highByte = spi.write(0);
+    lowByte = spi.write(0);
+    deselect();
+ 
+    if (lowByte & (1<<2)) {
+        error("No Probe");
+    } else {
+        value = (highByte << 5 | lowByte>>3);
+    }
+    
+    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;
+}
+ 
+void max6675::select() {
+    ss = 0;
+}
+ 
+void max6675::deselect() {
+    ss = 1;
+}
\ No newline at end of file

diff -r 000000000000 -r 33fb492d139e max6675.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/max6675.h	Mon Jun 08 23:18:38 2020 +0000
@@ -0,0 +1,26 @@
+#ifndef MAX6675_h
+#define MAX6675_h
+ 
+#include "mbed.h"
+ 
+class max6675
+{
+    SPI& spi;
+    DigitalOut ss;
+  public:
+  
+    max6675(SPI& _spi, PinName _ss);
+    
+    void select();
+    void deselect();
+    float read_temp();
+    
+  private:
+    PinName _CS_pin;
+    PinName _SO_pin;
+    PinName _SCK_pin;
+    int _units;
+    float _error;
+};
+ 
+#endif
\ No newline at end of file