Diff: ADIS16488.h

Revision:

30:96d133f3008e

Parent:

29:dead10cce6e9

--- a/ADIS16488.h	Thu Jan 09 14:09:05 2014 +0000
+++ b/ADIS16488.h	Mon Mar 03 13:19:31 2014 +0000
@@ -22,7 +22,7 @@
 union WD { long dataWord; unsigned short pt[2];} wd;
 
 //IMU records are buffered in the IMUDataReady ISR
-const unsigned char IMUrecArraySize = 10;
+const unsigned char IMUrecArraySize = 5;
 
 #pragma pack(1)
 struct IMUREC
@@ -42,16 +42,27 @@
 
 void IMUDataReadyISR(void)
 {   
-    IMUtimeFrom1PPS = timeFromPPS.read_us();        
+    IMURecordCounter++;
+   
+    IMUtimeFrom1PPS = timeFromPPS.read_us();    //timer reset to zero in the the GPS 1PPS
+    
+    //    GPSTimemsecs is taken from the GPS message -- but that may follow the 1PPS by several millisecs
+    //    PPSTimeOffset is set to zero after the time becomes available
+    //    so PPSTimeOffset accounts for the possible >1sec between the current IMU time and the time of the last PPS
+    //    this also accounts for a missed GPS time message that holds the GPS time  
     tempRec.GPSTime = GPSTimemsecs + PPSTimeOffset*1000 + IMUtimeFrom1PPS/1000.0;
     
+    //tempRec.GPSTime = PPSCounter*1000 + timeFromPPS.read_us()/1000;
+    
+    //test to see if we are ready to write the current IMU data buffer and swap the ping-pong buffer
     if (IMUClockCounter == IMUrecArraySize ) 
     {
-        IMUDataReady = true;
-        fillingPingWritingPong = !fillingPingWritingPong;
-        IMUClockCounter = 0;
+        IMUDataReady = true;  //signals the write in the main loop
+        fillingPingWritingPong = !fillingPingWritingPong; //swap the ping-pong buffer
+        IMUClockCounter = 0;  //reset the IMU record counter
     }
   
+    //
     spi.write((int) HIGH_REGISTER[0]); //next read will return results from HIGH_REGITER[0]
     for (int i=0; i<6; i++)  //read the 6 rate and accel variables
     {
@@ -61,13 +72,16 @@
         
         if ( fillingPingWritingPong) tempRec.dataWord[i] = wd.dataWord; //data word is a signed long
         else                         tempRec.dataWord[i] = wd.dataWord; //data word is a signed long
-    }           
+    }          
+    //
     
     //fill the correct buffer ping or pong
     if (fillingPingWritingPong)  imuPing[IMUClockCounter] = tempRec;
     else                         imuPong[IMUClockCounter] = tempRec;
+    //
     
     IMUClockCounter++;
+ 
     
     return;
 } 
@@ -97,7 +111,8 @@
     // The C abd D designate the registers for the DECRATE of Page 3
     // The 0x17 sets the rate to:  2460/(23+1) = 102.5Hz
     // The 0x18 sets the rate to:  2460/(24+1) =  98.4Hz
-    spi.write((int)0x8C17);    //write high byte  (only page number can be written in a single byte)
+    //spi.write((int)0x8C17);    //write high byte  (only page number can be written in a single byte)
+    spi.write((int)0x8C30);    //write high byte  (only page number can be written in a single byte)
     spi.write((int)0x8D00);    //write the low byte of DECRATE 
     
     //to set the GPS VARF clock as the input synch clock for the IMU