diff --git a/df_datalink_sp/src/networking/link_layer/time_sync.c b/df_datalink_sp/src/networking/link_layer/time_sync.c
index 9b55586..5dd7f49 100644
--- a/df_datalink_sp/src/networking/link_layer/time_sync.c
+++ b/df_datalink_sp/src/networking/link_layer/time_sync.c
@@ -32,20 +32,22 @@
 
 /*****************************************************************************/
 /**
- * @brief    a slot alignment, base on physical layer information.
+ * @brief    Get time deviation to the specified frame and slot number.
  *
  * @param   instPtr	a pointer to linklayer layer instance
  * @param   frameNum
  * @param   slotNum
+ * @param   relative
+ * @param   timeDev
  *
- * @return  SUCCESS Initialize successfully.
- *          FAILURE Initialization failed, allocate memory fail or initial
- *          bram controller fail.
+ * @return  SUCCESS
+ * 			EIGNORE there is no received frame
  *
  ******************************************************************************/
-// TODO: Check
-int32_t L2_TimeAlign(L2_INST *instPtr, uint32_t frameNum, uint32_t slotNum, bool relative)
+int32_t L2_GetTimeDeviation(L2_INST *instPtr, uint32_t frameNum, uint32_t slotNum, bool relative, int64_t *timeDev)
 {
+	ASSERT(instPtr != NULL);
+	ASSERT(timeDev != NULL);
 	L1_FRAME_TYPE lastRecvdFrame;
 	lastRecvdFrame = Phy_GetLastRecvFrameType(instPtr->config.phyInstPtr);
 	if (lastRecvdFrame == L1_NONE_FRAME)
@@ -57,8 +59,7 @@ int32_t L2_TimeAlign(L2_INST *instPtr, uint32_t frameNum, uint32_t slotNum, bool
 	DBG_INFO("Starting TimeAlign operation...\n");
 	// read nextSendTime from physical layer
 	uint64_t currTime, expectTime;
-	int64_t timeDiff;
-	TIME_WORD timeStamp, slotTimerAdjmet;
+	TIME_WORD timeStamp;
 	expectTime = ((uint64_t)(frameNum * L2_SLOTS_PER_FRAME + slotNum)) * TIME_FRAC_MAX;
 	expectTime += Phy_GetTimeComp(lastRecvdFrame);
 
@@ -71,10 +72,27 @@ int32_t L2_TimeAlign(L2_INST *instPtr, uint32_t frameNum, uint32_t slotNum, bool
 	currTime = (uint64_t)timeStamp.frac_part;
 	currTime += ((uint64_t)timeStamp.int_part) * TIME_FRAC_MAX;
 
-	timeDiff = (int64_t)(expectTime - currTime);
-
-	slotTimerAdjmet.int_part = (uint32_t)(timeDiff / TIME_FRAC_MAX);
-	slotTimerAdjmet.frac_part = (uint32_t)(timeDiff % TIME_FRAC_MAX);
-	TimeCtrl_TimeAdjust(instPtr->config.tmcInstPtr, &slotTimerAdjmet, TM_ADJ_ADD);
+	*timeDev = (int64_t)(expectTime - currTime);
 	return SUCCESS;
+}
+
+
+/*****************************************************************************/
+/**
+ * @brief    Implement time adjustment by applying time deviation.
+ *
+ * @param   instPtr	a pointer to linklayer layer instance
+ * @param   timeDev
+ *
+ * @return  NONE
+ *
+ ******************************************************************************/
+void L2_TimeAdjust(L2_INST *instPtr, const int64_t *timeDev) 
+{
+	ASSERT(instPtr != NULL);
+	ASSERT(timeDev != NULL);
+	TIME_WORD slotTimerAdjmet;
+	slotTimerAdjmet.int_part = (uint32_t)(*timeDev / TIME_FRAC_MAX);
+	slotTimerAdjmet.frac_part = (uint32_t)(*timeDev % TIME_FRAC_MAX);
+	TimeCtrl_TimeAdjust(instPtr->config.tmcInstPtr, &slotTimerAdjmet, TM_ADJ_ADD);
 }
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