diff --git a/src/main/scala/backBoard/Qei.scala b/src/main/scala/backBoard/Qei.scala
index 5aa2bd4..f9e0892 100644
--- a/src/main/scala/backBoard/Qei.scala
+++ b/src/main/scala/backBoard/Qei.scala
@@ -8,7 +8,7 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
   val phaseA    = for( i <- 0 until 2 ) yield { Wire(Bool()) }
   val phaseB    = for( i <- 0 until 2 ) yield { Wire(Bool()) }
   val phaseZ    = for( i <- 0 until 2 ) yield { Wire(Bool()) }
-  val counter   = for( i <- 0 until 2 ) yield { Reg(UInt(32.W)) }
+  val counter   = for( i <- 0 until 2 ) yield { Reg(UInt(33.W)) }
   val encordNxt = for( i <- 0 until 2 ) yield { Cat( phaseB(i), phaseA(i) ) }
   val encordCur = for( i <- 0 until 2 ) yield { RegNext(encordNxt(i)) }
 
@@ -23,8 +23,6 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
   val isSetValPos = for( i <- 0 until 2 ) yield { ~RegNext( isSetVal(i), false.B ) &  isSetVal(i) }
   val isSetValNeg = for( i <- 0 until 2 ) yield {  RegNext( isSetVal(i), false.B ) & ~isSetVal(i) }
 
-
-
   val isAdvA = for( i <- 0 until 2 ) yield {
     ( encordCur(i) === "b00".U & encordNxt(i) === "b01".U & mode(i).extract(1))   |
     ( encordCur(i) === "b01".U & encordNxt(i) === "b11".U & mode(i) =/= "b00".U ) |
@@ -44,6 +42,9 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
   // val isKeep = for( i <- 0 until 2 ) yield { encordCur(i) ===  encordNxt(i) } 
   val isOverflow = for( i <- 0 until 2 ) yield { Wire(Bool()) } 
 
+  val isCounter32Flip = for( i <- 0 until 2 ) yield { RegNext( counter(i).extract(32)) =/= counter(i).extract(32) }
+  val isCounter31Flip = for( i <- 0 until 2 ) yield { RegNext( counter(i).extract(31)) =/= counter(i).extract(31) }
+
 
   for( i <- 0 until 2 ){
 
@@ -60,7 +61,7 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
       when(isEnable(i)){
         when(~is2Phase(i)){ //A Phase only
           when( RegNext( phaseA(i) ) & ~phaseA(i) ){
-            when( isSetVal(i) & counter(i) === "hFFFFFFFF".U ){
+            when( isSetVal(i) & isCounter32Flip(i) ){
               isOverflow(i) := true.B
             } .otherwise{
               counter(i) := counter(i) + 1.U
@@ -72,13 +73,13 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
           } .elsewhen( isAdvA(i) ){
             when( isSign(i) ) {
               when( invDirect(i) ){
-                when( isSetVal(i) & counter(i) === "h80000000".U ){
+                when( isSetVal(i) & isCounter31Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) - 1.U
                 }
               } .otherwise{
-                when( isSetVal(i) & counter(i) === "h7FFFFFFF".U ){
+                when( isSetVal(i) & isCounter31Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) + 1.U
@@ -86,13 +87,13 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
               }
             } .otherwise{
               when( invDirect(i) ){
-                when( isSetVal(i) & counter(i) === 0.U ){
+                when( isSetVal(i) & isCounter32Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) - 1.U
                 }
               } .otherwise{
-                when( isSetVal(i) & counter(i) === "hFFFFFFFF".U ){
+                when( isSetVal(i) & isCounter32Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) + 1.U
@@ -102,13 +103,13 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
           } .elsewhen( isAdvB(i) ){
             when( isSign(i) ) {
               when( invDirect(i) ){
-                when( isSetVal(i) & counter(i) === "h7FFFFFFF".U ){
+                when( isSetVal(i) & isCounter31Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) + 1.U
                 }
               } .otherwise{
-                when( isSetVal(i) & counter(i) === "h80000000".U ){
+                when( isSetVal(i) & isCounter31Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) - 1.U
@@ -116,13 +117,13 @@ trait BackBoardSlvQei{ this: BackBoardSlvLocal =>
               }
             } .otherwise{
               when( invDirect(i) ){
-                when( isSetVal(i) & counter(i) === "hFFFFFFFF".U ){
+                when( isSetVal(i) & isCounter32Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) + 1.U
                 }
               } .otherwise{
-                when( isSetVal(i) & counter(i) === 0.U ){
+                when( isSetVal(i) & isCounter32Flip(i) ){
                   isOverflow(i) := true.B
                 } .otherwise{
                   counter(i) := counter(i) - 1.U