Diff: DS18B20.cpp

Revision:

2:8e118d297c83

Parent:

1:78f2fa466c55

--- a/DS18B20.cpp	Mon Dec 03 22:58:27 2012 +0000
+++ b/DS18B20.cpp	Tue May 27 17:03:27 2014 +0000
@@ -22,72 +22,89 @@
 
 DigitalOut conversionInProgress(LED4);  // conversion in progress
 DigitalOut resetFailure(LED1);          // for error reporting
-extern DigitalInOut sensor;     // sensor pin
+//extern DigitalInOut sensor;     // sensor pin
 
-static void inError() {
+static void inError()
+{
     while (1) {
         resetFailure = !resetFailure;
         wait(0.2);
     }
 }
 
-void DoConversion() {
-    if (Reset(sensor) != 0) {
+void DoConversion(DigitalInOut& pin)
+{
+    if (Reset(pin) != 0) {
         inError();
     } else {
         conversionInProgress = 1;       // led on
-        WriteByte(sensor, SKIP_ROM);            // Skip ROM
-        WriteByte(sensor, CONVERT);             // Convert
-        while (ReadBit(sensor) == 0) {
+        WriteByte(pin, SKIP_ROM);            // Skip ROM
+        WriteByte(pin, CONVERT);             // Convert
+        while (ReadBit(pin) == 0) {
             // wait for conversion to complete
         }
         conversionInProgress = 0;       // led off
     }
 }
 
-uint32_t GetTemperature() {
+uint32_t GetTemperature(DigitalInOut &pin)
+{
     uint32_t result = 0;
-    if (Reset(sensor) != 0) {
+    if (Reset(pin) != 0) {
         inError();
     } else {
         ScratchPad_t scratchpad;
-        WriteByte(sensor, SKIP_ROM);    // Skip ROM
-        WriteByte(sensor, READ_SCRATCHPAD);    // Read Scrachpad
-        scratchpad.LSB = ReadByte(sensor);
-        scratchpad.MSB = ReadByte(sensor);
-        Reset(sensor);    // terminate read as we only want temperature
+        WriteByte(pin, SKIP_ROM);    // Skip ROM
+        WriteByte(pin, READ_SCRATCHPAD);    // Read Scrachpad
+        scratchpad.LSB = ReadByte(pin);
+        scratchpad.MSB = ReadByte(pin);
+        Reset(pin);    // terminate read as we only want temperature
+
         result = ((scratchpad.MSB << 8) | scratchpad.LSB);
+        
     }
     return result;
 }
 
-ROM_Code_t ReadROM() {
+ROM_Code_t ReadROM(DigitalInOut &pin)
+{
     ROM_Code_t ROM_Code;
-    if (Reset(sensor) != 0) {
+    if (Reset(pin) != 0) {
         inError();
     } else {
-        
-        WriteByte(sensor, READ_ROM);    // Read ROM
+
+        WriteByte(pin, READ_ROM);    // Read ROM
         for (uint32_t i = 0; i < 8; ++i) {
-            ROM_Code.rom[i] = ReadByte(sensor);
+            ROM_Code.rom[i] = ReadByte(pin);
         }
     }
     return ROM_Code;
 }
 
 // temperature is store as 7.4 fixed point format (assuming 12 bit conversion)
-void displayTemperature(Serial& s) {
-    DoConversion();
-    uint32_t temp = GetTemperature();
+void displayTemperature(Serial& s, DigitalInOut& pin)
+{
+    DoConversion(pin);
+    uint32_t temp = GetTemperature(pin);
     float f = (temp & 0x0F) * 0.0625;    // calculate .4 part
     f += (temp >> 4);    // add 7.0 part to it
-    s.printf("Temp is %2.1fC\n\r", f);    // display in 2.1 format
+    s.printf("Temp is %2.2fC\n\r", f);    // display in 2.1 format
 }
 
-float getTemp(){
-    DoConversion();
-    uint32_t temp = GetTemperature();
-    float f = (temp & 0x0F) * 0.0625;    // calculate .4 part
-    f += (temp >> 4);    // add 7.0 part to it
+float getTemp(DigitalInOut &pin)
+{
+    DoConversion(pin);
+    uint32_t temp = GetTemperature(pin);
+    float f;
+    if((temp & 0xff00)== 0xff00){
+       temp = ~temp + 1;
+       f = (temp & 0x000F) * 0.0625;    // calculate .4 part
+       f += ((temp >> 4)&0x000f);    // add 7.0 part to it
+       f = -f;
+    }else{
+       f = (temp & 0x000F) * 0.0625;    // calculate .4 part
+       f += (temp >> 4);    // add 7.0 part to it
+    }
+   // s.printf("T = %x | mask = %x | %2.2f\n", temp, (temp & 0xff00), f);
     return f;
 }