1 files changed, 117 insertions, 0 deletions
diff --git a/src/pmdas/roomtemp/dsread.c b/src/pmdas/roomtemp/dsread.c
new file mode 100644
index 0000000..5ac8474
--- /dev/null
+++ b/src/pmdas/roomtemp/dsread.c
@@ -0,0 +1,117 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "mlan/mlan.h"
+
+//----------------------------------------------------------------------
+// Read the temperature of a DS1820
+//
+// 'SerialNum'   - Serial Number of DS1820 to read temperature from
+// 'Temp '       - pointer to variable where that temperature will be 
+//                 returned
+//
+// Returns: TRUE(1)  temperature has been read and verified
+//          FALSE(0) could not read the temperature, perhaps device is not
+//                   in contact
+//
+int ReadTemperature(uchar SerialNum[8], float *Temp)
+{
+   int rt=FALSE;
+   uchar send_block[30];
+   int send_cnt=0, tsht, i;
+   float tmp,cr,cpc;
+   DOWCRC = 0;
+
+   // set the device serial number to the counter device
+   MLanSerialNum(SerialNum,FALSE);
+
+   // access the device 
+   if (MLanAccess())
+   {
+      // send the convert temperature command
+      MLanTouchByte(0x44);
+
+      // set the MicroLAN to strong pull-up
+      if (MLanLevel(MODE_STRONG5) != MODE_STRONG5)
+         return FALSE;
+ 
+      // sleep for 1 second
+      msDelay(1000);
+
+      // turn off the MicroLAN strong pull-up
+      if (MLanLevel(MODE_NORMAL) != MODE_NORMAL)
+         return FALSE;
+
+      // access the device 
+      if (MLanAccess())
+      {
+         // create a block to send that reads the temperature
+         // read scratchpad command
+         send_block[send_cnt++] = 0xBE;
+         // now add the read bytes for data bytes and crc8
+         for (i = 0; i < 9; i++)
+            send_block[send_cnt++] = 0xFF;
+
+         // now send the block
+         if (MLanBlock(FALSE,send_block,send_cnt))
+         {
+            // perform the CRC8 on the last 8 bytes of packet
+            for (i = send_cnt - 9; i < send_cnt; i++)
+               dowcrc(send_block[i]);
+
+            // verify CRC8 is correct
+            if (DOWCRC == 0x00)
+            {
+               // calculate the high-res temperature
+               tsht = send_block[1];
+               if (send_block[2] & 0x01)
+                  tsht |= -256;
+               tmp = (float)(tsht/2);
+               cr = send_block[7];
+               cpc = send_block[8];
+               if (cpc == 0)
+                  return FALSE;   
+               else
+                  tmp = tmp - (float)0.25 + (cpc - cr)/cpc;
+   
+               *Temp = tmp;
+               // success
+               rt = TRUE;
+            }
+         }
+      }
+   }
+   
+   // return the result flag rt
+   return rt;
+}
+
+/*
+ * find next temperature sensor
+ */
+unsigned char *
+nextsensor(void)
+{
+    static unsigned char	sn[8];
+    static int			first = 1;
+
+    if (first) {
+	// set the search to first find for temperature family code
+	MLanFamilySearchSetup(TEMP_FAMILY);
+	first = 0;
+    }
+
+    for ( ; ; ) {
+	// perform the search
+	if (!MLanNext(TRUE, FALSE)) {
+	    return NULL;
+	}
+	// get serial number and verify the family code
+	MLanSerialNum(sn, TRUE);
+	if (sn[0] == TEMP_FAMILY)
+	    return sn;
+    }
+}