Diff: ds18b20.cpp

Revision:

5:6226f3c566ef

Parent:

4:e076884ef8bd

Child:

6:be97d38e0b01

--- a/ds18b20.cpp	Tue May 03 09:23:26 2016 +0000
+++ b/ds18b20.cpp	Wed May 11 16:42:35 2016 +0000
@@ -12,6 +12,8 @@
 static int sendlen = 0;
 static int recvlen = 0;
 
+uint16_t DS18B20Value;
+
 void DS18B20ReadRom()
 {
     sendlen = 1;
@@ -20,11 +22,12 @@
     OneWireExchange(sendlen, recvlen, send, recv, 0);
 }
 void DS18B20ReadScratchpad()
-{
+{   
     sendlen = 2;
     send[0] = 0xCC;
     send[1] = 0xBE;
     recvlen = 9;
+    for (int i = 0; i < recvlen; i++) recv[i] = 0;
     OneWireExchange(sendlen, recvlen, send, recv, 0);
 }
 void DS18B20ConvertT()
@@ -33,17 +36,52 @@
     send[0] = 0xCC;
     send[1] = 0x44;
     recvlen = 0;
+    for (int i = 0; i < recvlen; i++) recv[i] = 0;
     OneWireExchange(sendlen, recvlen, send, recv, 750);
 }
-int DS18B20Init()
+#define IDLE                0
+#define CONVERT_T           1
+#define READ_SCRATCH_PAD    2
+#define EXTRACT_TEMPERATURE 3
+static int state = IDLE;
+static int handlestate()
 {
-    ticker.attach(&DS18B20ReadScratchpad, 10.0);
+    if (OneWireBusy()) return 0;
+    
+    switch (state)
+    {
+        case IDLE:
+            break;
+        case CONVERT_T:
+            DS18B20ConvertT();
+            state = READ_SCRATCH_PAD;
+            break;
+        case READ_SCRATCH_PAD:
+            DS18B20ReadScratchpad();
+            state = EXTRACT_TEMPERATURE;
+            break;
+        case EXTRACT_TEMPERATURE:
+            if (OneWireCrc())
+            {
+                DS18B20Value = 0xFFFF;
+            }
+            else
+            {
+                DS18B20Value = recv[1];
+                DS18B20Value <<= 8;
+                DS18B20Value |= recv[0];
+            }
+            state = IDLE;
+            break;
+        default:
+            LogF("Unknown DS18B20 state %d\r\n", state);
+            return -1;
+    }
     return 0;
 }
-int DS18B20Main()
+static void logcomms()
 {
     static int wasbusy = false;
-
     if (!OneWireBusy() && wasbusy)
     {
         LogF("1-wire | send:");
@@ -52,7 +90,24 @@
         for (int i = 0; i < recvlen; i++) LogF(" %02x", recv[i]);
         LogF("\r\n");
     }
-
     wasbusy = OneWireBusy();
+}
+static void timed()
+{
+    state = CONVERT_T;
+}
+int DS18B20Init()
+{
+    ticker.attach(&timed, 10.0);
+    return 0;
+}
+int DS18B20Main()
+{
+    logcomms();
+    
+    int r = handlestate();
+    
+    if (r) return -1;
+    
     return 0;
 }
\ No newline at end of file