Revision 0:d76559dea000, committed 2013-06-23

Comitter:

simonbarker

Date:

Sun Jun 23 15:18:52 2013 +0000

Commit message:

Finalised DS18B20 methods

Changed in this revision

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