Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -re54806da466a8c52e19fd272356dbbfde04171fd -r359f9350ad9b2156ce02c94fa4950c4fb6768572
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision e54806da466a8c52e19fd272356dbbfde04171fd)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 359f9350ad9b2156ce02c94fa4950c4fb6768572)
@@ -57,6 +57,9 @@
 #define MSG_NOT_ACKED_MAX_RETRIES       3       ///< Maximum number of times a message that requires ACK that was not ACK'd can be re-sent before alarm
 #define PENDING_ACK_LIST_SIZE           25      ///< Maximum number of Denali messages that can be pending ACK at any given time
 
+#define MAX_FPGA_CLOCK_SPEED_ERRORS             3                                     ///< maximum number of FPGA clock speed errors within window period before alarm - // DN-16SEPT2022
+#define MAX_FPGA_CLOCK_SPEED_ERROR_WINDOW_MS    (10 * SEC_PER_MIN * MS_PER_SECOND)    ///< FPGA clock speed error window - // DN-16SEPT2022
+
 #pragma pack(push, 1)
 
 /// Record for transmitted message that is pending acknowledgment from receiver.
@@ -148,6 +151,9 @@
 
     // Initialize bad message CRC time windowed count
     initTimeWindowedCount( TIME_WINDOWED_COUNT_BAD_MSG_CRC, MAX_COMM_CRC_FAILURES, MAX_COMM_CRC_FAILURE_WINDOW_MS );
+
+    // initialize FPGA clock speed error time windowed count
+    initTimeWindowedCount( TIME_WINDOWED_COUNT_FPGA_CLOCK_SPEED_ERROR, MAX_FPGA_CLOCK_SPEED_ERRORS, MAX_FPGA_CLOCK_SPEED_ERROR_WINDOW_MS);   // DN-16SEPT2022
 
     // Initialize pending ACK list
     for ( i = 0; i < PENDING_ACK_LIST_SIZE; i++ )