Index: firmware/App/Services/FPGA.c
===================================================================
diff -u -reb877ae36c28eb83553ee11ccccf42e2c4a5b4d2 -reff7b1575f008f81b29ef906f6346fac6012d3ab
--- firmware/App/Services/FPGA.c	(.../FPGA.c)	(revision eb877ae36c28eb83553ee11ccccf42e2c4a5b4d2)
+++ firmware/App/Services/FPGA.c	(.../FPGA.c)	(revision eff7b1575f008f81b29ef906f6346fac6012d3ab)
@@ -63,6 +63,8 @@
 #define SCI2_RECEIVE_DMA_REQUEST        28
 #define SCI2_TRANSMIT_DMA_REQUEST       29
 
+#define MAX_COMM_ERROR_RETRIES          5
+
 // FPGA Sensors Record
 #pragma pack(push,1)
 typedef struct
@@ -98,6 +100,7 @@
 // FPGA state
 static FPGA_STATE_T fpgaState = FPGA_STATE_START;
 
+static U32 fpgaCommRetryCount = 0;
 static U32 fpgaReceiptCounter = 0;
 static U32 fpgaTransmitCounter = 0;
 static BOOL fpgaWriteCommandInProgress = FALSE;
@@ -158,6 +161,12 @@
     memset( &fpgaSensorReadings, 0, sizeof(FPGA_SENSORS_T) );
     memset( &fpgaActuatorSetPoints, 0, sizeof(FPGA_ACTUATORS_T) );
 
+    // initialize fpga comm buffers
+    memset( &fpgaWriteCmdBuffer, 0, FPGA_WRITE_CMD_BUFFER_LEN );
+    memset( &fpgaReadCmdBuffer, 0, FPGA_READ_CMD_BUFFER_LEN );
+    memset( &fpgaWriteResponseBuffer, 0, FPGA_WRITE_RSP_BUFFER_LEN );
+    memset( &fpgaReadResponseBuffer, 0, FPGA_READ_RSP_BUFFER_LEN );
+
     // enable interrupt notifications for FPGA serial port
     sciEnableNotification( scilinREG, SCI_OE_INT | SCI_FE_INT );
 
@@ -296,13 +305,11 @@
     // see if we want to follow up with a bulk read command
     if ( TRUE == fpgaBulkWriteAndReadInProgress )
     {
-        // first receipt?
-        if ( 1 == fpgaReceiptCounter )
-        {
-            fpgaBulkWriteAndReadInProgress = FALSE;
-            fpgaReadCommandInProgress = TRUE;
-            // TODO - initiate bulk read command
-        }
+        fpgaBulkWriteAndReadInProgress = FALSE;
+        fpgaReadCommandInProgress = TRUE;
+        // initiate bulk read command
+        startDMAReceiptOfReadResp();
+        startDMAReadCmd();
     }
 }
 
@@ -343,8 +350,8 @@
             fpgaState = handleFPGAReceiveHeaderState();
             break;
 
+        // TODO - sensor/ADC init/configuration states
 
-
         case FPGA_STATE_RCV_ALL_SENSORS:
             fpgaState = handleFPGAReceiveAllSensorsState();
             break;
@@ -365,6 +372,12 @@
             break;
     }
 
+    // if retries for commands exceeds limit, fault
+    if ( fpgaCommRetryCount > MAX_COMM_ERROR_RETRIES )
+    {
+        // TODO - FPGA comm fault
+    }
+
     // reset comm flags after processing incoming responses
     resetFPGACommFlags();
 }
@@ -387,8 +400,8 @@
             fpgaState = handleFPGAReadHeaderState();
             break;
 
+        // TODO - sensor/ADC init/configuration states
 
-
         case FPGA_STATE_WRITE_ALL_ACTUATORS:
             fpgaState = handleFPGAWriteAllActuatorsState();
             break;
@@ -463,17 +476,32 @@
         // did FPGA Ack the read command?
         if ( fpgaReadResponseBuffer[0] == FPGA_READ_CMD_ACK )
         {
+            U32 rspSize = FPGA_READ_RSP_HDR_LEN + sizeof(FPGA_HEADER_T);
+            U32 crcPos = rspSize;
+            U16 crc = MAKE_WORD_OF_BYTES( fpgaReadResponseBuffer[crcPos+1], fpgaReadResponseBuffer[crcPos] );
+
             // does the FPGA response CRC check out?
-            if ( 1 ) // TODO - check response CRC
-            {   // capture the read values
+            if ( crc == crc16( fpgaReadResponseBuffer, rspSize ) )
+//            if ( 1 ) // TODO - remove when FPGA CRCs are implemented
+            {
+                fpgaCommRetryCount = 0;
+                // capture the read values
                 memcpy( &fpgaHeader, &fpgaReadResponseBuffer[1], sizeof(FPGA_HEADER_T) );
                 result = FPGA_STATE_WRITE_ALL_ACTUATORS;
             }
+            else
+            {
+                fpgaCommRetryCount++;
+            }
         }
+        else  // header read was NAK'd
+        {
+            fpgaCommRetryCount++;
+        }
     }
-    else //
+    else // no response to read command
     {
-
+        fpgaCommRetryCount++;
     }
 
     // shouldn't be any data received at this time
@@ -499,7 +527,7 @@
 
     // construct bulk write command to write actuator data registers starting at address 3  (TODO - change address later)
     fpgaWriteCmdBuffer[0] = FPGA_WRITE_CMD_CODE;
-    fpgaWriteCmdBuffer[1] = 0x02;    // start at FPGA address 8
+    fpgaWriteCmdBuffer[1] = 0x08;    // start at FPGA address 8
     fpgaWriteCmdBuffer[2] = 0x00;
     fpgaWriteCmdBuffer[3] = 1;  // TODO - replace 1 with sizeof(FPGA_ACTUATORS_T)
 //    memcpy( &(fpgaWriteCmdBuffer[FPGA_WRITE_CMD_HDR_LEN]), &fpgaActuatorSetPoints, sizeof(FPGA_ACTUATORS_T) );
@@ -548,7 +576,7 @@
     // check bulk write command success
     if ( ( FALSE == fpgaWriteCommandResponseReceived ) || ( fpgaWriteResponseBuffer[0] != FPGA_WRITE_CMD_ACK ) )
     {
-        // TODO - ???
+        fpgaCommRetryCount++;
     }
 
     // if bulk read command is ACK'd, collect the readings
@@ -557,17 +585,32 @@
         // did FPGA Ack the read command?
         if ( fpgaReadResponseBuffer[0] == FPGA_READ_CMD_ACK )
         {
+            U32 rspSize = FPGA_READ_RSP_HDR_LEN + sizeof(FPGA_SENSORS_T);
+            U32 crcPos = rspSize;
+            U16 crc = MAKE_WORD_OF_BYTES( fpgaReadResponseBuffer[crcPos+1], fpgaReadResponseBuffer[crcPos] );
+
             // does the FPGA response CRC check out?
-            if ( 1 ) // TODO - check response CRC
-            {   // capture the read values
-                memcpy( &fpgaSensorReadings, fpgaReadResponseBuffer, sizeof(FPGA_SENSORS_T) );
+            if ( crc == crc16( fpgaReadResponseBuffer, rspSize ) )
+//            if ( 1 ) // TODO - remove when FPGA CRCs are implemented
+            {
+                fpgaCommRetryCount = 0;
+                // capture the read values
+                memcpy( &fpgaSensorReadings, &fpgaReadResponseBuffer[1], sizeof(FPGA_SENSORS_T) );
                 result = FPGA_STATE_WRITE_ALL_ACTUATORS;
             }
+            else // bad CRC
+            {
+                fpgaCommRetryCount++;
+            }
         }
+        else // read command was NAK'd
+        {
+            fpgaCommRetryCount++;
+        }
     }
-    else
+    else // no response to read command
     {
-        // TODO - ???
+        fpgaCommRetryCount++;
     }
 
     // shouldn't be any data received at this time
@@ -610,7 +653,15 @@
  *************************************************************************/
 static void setupDMAForWriteCmd( U32 bytes2Transmit )
 {
-    fpgaDMAWriteControlRecord.FRCNT = bytes2Transmit;
+    // verify # of bytes does not exceed buffer length
+    if ( bytes2Transmit <= FPGA_WRITE_CMD_BUFFER_LEN )
+    {
+        fpgaDMAWriteControlRecord.FRCNT = bytes2Transmit;
+    }
+    else
+    {
+        // TODO - s/w fault
+    }
 }
 
 /*************************************************************************
@@ -642,7 +693,15 @@
  *************************************************************************/
 static void setupDMAForWriteResp( U32 bytes2Receive )
 {
-    fpgaDMAWriteRespControlRecord.FRCNT = bytes2Receive;
+    // verify # of bytes does not exceed buffer length
+    if ( bytes2Receive <= FPGA_WRITE_RSP_BUFFER_LEN )
+    {
+        fpgaDMAWriteRespControlRecord.FRCNT = bytes2Receive;
+    }
+    else
+    {
+        // TODO - s/w fault
+    }
 }
 
 /*************************************************************************
@@ -674,7 +733,15 @@
  *************************************************************************/
 static void setupDMAForReadCmd( U32 bytes2Transmit )
 {
-    fpgaDMAReadControlRecord.FRCNT = bytes2Transmit;
+    // verify # of bytes does not exceed buffer length
+    if ( bytes2Transmit <= FPGA_READ_CMD_BUFFER_LEN )
+    {
+        fpgaDMAReadControlRecord.FRCNT = bytes2Transmit;
+    }
+    else
+    {
+        // TODO - s/w fault
+    }
 }
 
 /*************************************************************************
@@ -706,7 +773,15 @@
  *************************************************************************/
 static void setupDMAForReadResp( U32 bytes2Receive )
 {
-    fpgaDMAReadRespControlRecord.FRCNT = bytes2Receive;
+    // verify # of bytes does not exceed buffer length
+    if ( bytes2Receive <= FPGA_READ_RSP_BUFFER_LEN )
+    {
+        fpgaDMAReadRespControlRecord.FRCNT = bytes2Receive;
+    }
+    else
+    {
+        // TODO - s/w fault
+    }
 }
 
 /*************************************************************************