DS18B20

Fork of DS18B20 by Simon Barker

Files at this revision

API Documentation at this revision

Comitter:
simonbarker
Date:
Sun Jun 23 15:18:52 2013 +0000
Commit message:
Finalised DS18B20 methods

Changed in this revision

DS18B20.cpp Show annotated file Show diff for this revision Revisions of this file
DS18B20.h Show annotated file Show diff for this revision Revisions of this file
diff -r 000000000000 -r d76559dea000 DS18B20.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS18B20.cpp	Sun Jun 23 15:18:52 2013 +0000
@@ -0,0 +1,66 @@
+#include "DS18B20.h"
+
+DS18B20::DS18B20(PinName oneBus):oneBus_(oneBus){
+
+}
+
+/*
+    send message to every sensor on the bus to take a reading
+*/
+
+void DS18B20::broadcastConvert() {
+    //broadcast that temp conversions should begin, all at once so saves time
+    oneBus_.init();
+    oneBus_.writeByte(0xCC);
+    oneBus_.writeByte(0x44);
+
+    while (1) {
+        if (oneBus_.readBit())
+            break;
+    }
+}
+
+/*
+    retrieve temperatures from sensors
+*/
+
+float DS18B20::getTemperature(unsigned char* address) {
+    //get temperature from the device with address address
+    float temperature;
+    int scratchPad[9] = {0,0,0,0,0,0,0,0,0};
+
+    oneBus_.init();
+    oneBus_.writeByte(0x55);
+    for (int i = 0; i < 8; i++)
+        oneBus_.writeByte(address[i]);
+    oneBus_.writeByte(0xBE);
+
+    for (int i = 0; i < 2; i++) {
+        scratchPad[i] = oneBus_.readByte();
+    }
+    oneBus_.init();
+    temperature = ((scratchPad[1] * 256) + scratchPad[0])*0.0625;
+
+    return temperature;
+}
+
+/*
+    retrieve address of sensor and print to terminal
+*/
+
+void DS18B20::printSingleAddress() {
+    oneBus_.init();
+    //attach one sensor to port 25 and this will print out it's address
+    unsigned char address[8]= {0,0,0,0,0,0,0,0};
+
+    oneBus_.writeByte(0x33);
+
+    for (int i = 0; i<8; i++)
+        address[i] = oneBus_.readByte();
+    for (int i = 0; i<8; i++)
+        printf("0x%x,",address[i]);
+    
+    //check crc
+    unsigned char crc = oneBus_.CRC(address, 7);
+    printf("crc = %x \r\n",crc);
+}
\ No newline at end of file
diff -r 000000000000 -r d76559dea000 DS18B20.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DS18B20.h	Sun Jun 23 15:18:52 2013 +0000
@@ -0,0 +1,18 @@
+#ifndef DS18B20_h
+#define DS18B20_h
+
+#include "mbed.h"
+#include "Onewire.h"
+
+class DS18B20{
+
+public:
+  DS18B20(PinName oneBus);
+  void broadcastConvert();
+  float getTemperature(unsigned char* address);
+  void printSingleAddress();
+
+private:
+  Onewire oneBus_;
+};
+#endif
\ No newline at end of file