i dont think any improvememnts werre made

Impedance.c

@@ -81,39 +81,24 @@ int32_t AppIMPCtrl(uint32_t Command, void *pPara)
   {
     case IMPCTRL_START:
     {
-      // CRITICAL CHANGE: Use Manual Triggering for Sweep to avoid timing hazards
+      // Unified Start Logic: Always use Manual Trigger + ENDSEQ Interrupt
-      if(AppIMPCfg.SweepCfg.SweepEn)
+      AD5940_WUPTCtrl(bFALSE); 
-      {
+      
-          // Trigger first sequence manually
+      AD5940_INTCCfg(AFEINTC_1, AFEINTSRC_ENDSEQ, bTRUE);
-          AD5940_SEQMmrTrig(SEQID_0);
+      AD5940_INTCCfg(AFEINTC_1, AFEINTSRC_DATAFIFOTHRESH, bFALSE); 
-      }
+      AD5940_INTCClrFlag(AFEINTSRC_ALLINT);
-      else
-      {
-          // Use WUPT for Continuous Measure (fixed frequency)
-          WUPTCfg_Type wupt_cfg;
-          if(AD5940_WakeUp(10) > 10) return AD5940ERR_WAKEUP;
-          if(AppIMPCfg.IMPInited == bFALSE) return AD5940ERR_APPERROR;
-          
-          wupt_cfg.WuptEn = bTRUE;
-          wupt_cfg.WuptEndSeq = WUPTENDSEQ_A;
-          wupt_cfg.WuptOrder[0] = SEQID_0;
-          wupt_cfg.SeqxSleepTime[SEQID_0] = 4;
-          
-          uint32_t wait_cycles = (uint32_t)(AppIMPCfg.WuptClkFreq/AppIMPCfg.ImpODR);
-          if(wait_cycles < 20) wait_cycles = 20; 
-          wupt_cfg.SeqxWakeupTime[SEQID_0] = wait_cycles - 4;
-          
-          AD5940_WUPTCfg(&wupt_cfg);
-      }
       
       AppIMPCfg.FifoDataCount = 0;
+      AppIMPCfg.StopRequired = bFALSE;
+      
+      // Trigger first sequence manually
+      AD5940_SEQMmrTrig(SEQID_0);
       break;
     }
     case IMPCTRL_STOPNOW:
     {
       if(AD5940_WakeUp(10) > 10) return AD5940ERR_WAKEUP;
       AD5940_WUPTCtrl(bFALSE);
-      AD5940_WUPTCtrl(bFALSE);
       AD5940_SEQCtrlS(bFALSE); 
       break;
     }
@@ -359,7 +344,11 @@ static AD5940Err AppIMPSeqMeasureGen(void)
                 AFECTRL_SINC2NOTCH, bFALSE);
   AD5940_SEQGpioCtrlS(0); 
 
-  AD5940_EnterSleepS();
+  // REMOVED: AD5940_EnterSleepS(); 
+  // Keeping AFE active during sweep to prevent wake-up instability.
+
+  // CRITICAL FIX: Must stop sequencer to generate ENDSEQ interrupt
+  AD5940_SEQGenInsert(SEQ_STOP()); 
 
   error = AD5940_SEQGenFetchSeq(&pSeqCmd, &SeqLen);
   AD5940_SEQGenCtrl(bFALSE); 
@@ -397,6 +386,8 @@ AD5940Err AppIMPCheckFreq(float freq)
         AppIMPCfg.AdcClkFreq = 16e6;
         AppIMPCfg.SysClkFreq = 16000000.0;
         AD5940_HPModeEn(bFALSE);
+        // Allow clock to settle before further SPI writes
+        AD5940_Delay10us(50); 
     }
   }
   else
@@ -406,6 +397,8 @@ AD5940Err AppIMPCheckFreq(float freq)
         AppIMPCfg.AdcClkFreq = 32e6;
         AppIMPCfg.SysClkFreq = 32000000.0;
         AD5940_HPModeEn(bTRUE);
+        // Allow clock to settle before further SPI writes
+        AD5940_Delay10us(50);
     }
   }
   
@@ -501,6 +494,9 @@ int32_t AppIMPInit(uint32_t *pBuffer, uint32_t BufferSize)
   AD5940_SEQCfg(&seq_cfg); 
   AD5940_SEQMmrTrig(AppIMPCfg.InitSeqInfo.SeqId);
   
+  // CRITICAL FIX: Ensure ENDSEQ interrupt is enabled for Init Sequence
+  AD5940_INTCCfg(AFEINTC_1, AFEINTSRC_ENDSEQ, bTRUE);
+  
   // Safety timeout for Init Sequence
   int timeout = 100000;
   while(AD5940_INTCTestFlag(AFEINTC_1, AFEINTSRC_ENDSEQ) == bFALSE) {
@@ -593,7 +589,8 @@ int32_t AppIMPDataProcess(int32_t * const pData, uint32_t *pDataCount)
     else
         ZMag = 0;
 
-    ZPhase = PhaseV - PhaseI;
+    // Correct Phase: TIA inverts current, so we add 180 degrees (PI)
+    ZPhase = PhaseV - PhaseI + MATH_PI;
     
     // Normalize Phase to -PI to +PI
     while(ZPhase > MATH_PI) ZPhase -= 2*MATH_PI;
@@ -626,43 +623,66 @@ int32_t AppIMPISR(void *pBuff, uint32_t *pCount)
   if(AD5940_WakeUp(10) > 10) return AD5940ERR_WAKEUP;
   AD5940_SleepKeyCtrlS(SLPKEY_LOCK); 
 
-  if(AD5940_INTCTestFlag(AFEINTC_0, AFEINTSRC_DATAFIFOTHRESH) == bTRUE)
+  // Check Interrupt Source
-  {
+  uint32_t IntFlag = AD5940_INTCGetFlag(AFEINTC_1);
-    FifoCnt = (AD5940_FIFOGetCnt()/6)*6; // Align to 6 words
-    
-    if (FifoCnt == 0) {
-        // Safety: If interrupt fired but no data, clear flag and exit
-        AD5940_INTCClrFlag(AFEINTSRC_DATAFIFOTHRESH);
-        AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK);
-        return 0;
-    }
 
-    if(FifoCnt > BuffCount)
+  // Unified ISR: Handle ENDSEQ for both Sweep and Measure modes
-    {
+  if(IntFlag & AFEINTSRC_ENDSEQ)
-       FifoCnt = BuffCount;
+  {
-    }
+      // FIFO Latency Wait: Wait for data to arrive.
-    AD5940_FIFORd((uint32_t *)pBuff, FifoCnt);
+      // Use a real delay loop to ensure we don't timeout prematurely.
-    AD5940_INTCClrFlag(AFEINTSRC_DATAFIFOTHRESH);
+      int timeout = 100; 
-    
+      while(AD5940_FIFOGetCnt() < 6 && timeout-- > 0)
-    // Update Frequency
+      {
-    if (AppIMPRegModify(pBuff, &FifoCnt) == AD5940ERR_OK) 
+          AD5940_Delay10us(10); // Wait 100us per check
-    {
+      }
-        // CRITICAL: Manual Trigger Chain for Sweep
+
-        if(AppIMPCfg.SweepCfg.SweepEn)
+      // Read all available data
-        {
+      FifoCnt = (AD5940_FIFOGetCnt()/6)*6;
-            // Only trigger next if we haven't reached the count
+      if(FifoCnt > BuffCount) FifoCnt = BuffCount;
-            if(AppIMPCfg.FifoDataCount < AppIMPCfg.NumOfData)
+      
-            {
+      AD5940_FIFORd((uint32_t *)pBuff, FifoCnt);
-                AD5940_SEQMmrTrig(SEQID_0);
+      AD5940_INTCClrFlag(AFEINTSRC_ENDSEQ);
-            }
+      
-        }
+      // CRITICAL: Only advance if we actually got data.
-    }
+      // If FifoCnt is 0, it means we missed the data or it hasn't arrived.
-    
+      // Advancing the sweep in this case causes desynchronization.
-    AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK); 
+      if (FifoCnt > 0) 
-    AppIMPDataProcess((int32_t*)pBuff, &FifoCnt); 
+      {
-    *pCount = FifoCnt;
+          // Update Frequency (Sweep) or Check Limits (Measure)
-    return 0;
+          if (AppIMPRegModify(pBuff, &FifoCnt) == AD5940ERR_OK) 
+          {
+              if(AppIMPCfg.FifoDataCount < AppIMPCfg.NumOfData || AppIMPCfg.NumOfData == -1)
+              {
+                  if(AppIMPCfg.StopRequired == bFALSE)
+                  {
+                      // SRAM Write Settling: AppIMPRegModify writes to SRAM in Sweep Mode.
+                      AD5940_Delay10us(20); 
+
+                      // SEQ_STOP Side Effects: Toggle Sequencer Enable
+                      AD5940_SEQCtrlS(bFALSE);
+                      AD5940_SEQCtrlS(bTRUE);
+                      AD5940_SEQMmrTrig(SEQID_0);
+                  }
+              }
+          }
+          
+          AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK); 
+          AppIMPDataProcess((int32_t*)pBuff, &FifoCnt); 
+          *pCount = FifoCnt;
+      }
+      else
+      {
+          // Error Recovery: If we got ENDSEQ but no data, clear flags and unlock.
+          // We do NOT trigger the next point to avoid runaway errors.
+          AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK);
+          *pCount = 0;
+      }
+      return 0;
   }
   
+  // Clear any other spurious flags
+  AD5940_INTCClrFlag(AFEINTSRC_ALLINT);
+  AD5940_SleepKeyCtrlS(SLPKEY_UNLOCK);
   return 0;
 }