diff --git a/src/main/scala/backBoard/SpiSlv.scala b/src/main/scala/backBoard/SpiSlv.scala
index 66c2ceb..62841bf 100644
--- a/src/main/scala/backBoard/SpiSlv.scala
+++ b/src/main/scala/backBoard/SpiSlv.scala
@@ -66,9 +66,12 @@ trait BackBoardSpiSlv{ this: BackBoardSlvLocal =>
       bitSel   := 0.U
       byteSel  := 0.U
       cmd_100M := 0.U
-      exReg_100M := upReg(0)
     } .elsewhen( isSckPosedge & ~shiftCSn(1) & byteSel === 0.U ){ //CS为低，且SCK上跳的第0byte
       cmd_100M := Cat( cmd_100M(6,0), shiftMOSI(1) )
+    }
+
+    when( shiftCSn(2) & ~shiftCSn(1) ){  //CS下跳
+      exReg_100M := upReg(0)
     } .elsewhen( isSckPosedgeNext(1) & ~shiftCSn(1) & bitSel === 0.U ){ //CS为低，且SCK上跳补一拍 的第0bit
       when( byteSel === 1.U ){
         exReg_100M := upReg(1)
@@ -83,6 +86,7 @@ trait BackBoardSpiSlv{ this: BackBoardSlvLocal =>
       exReg_100M := Cat( exReg_100M(6 ,0), shiftMOSI(1) )
     }
 
+
     when(  isSckPosedgeNext(1) & ~shiftCSn(1) & byteSel === 3.U & bitSel === 0.U & spiCmd === 3.U ){
       exMask_100M := Cat( exReg_100M, exMask_100M(7,0) )
     } .elsewhen(  isSckPosedgeNext(1) & ~shiftCSn(1) & byteSel === 4.U & bitSel === 0.U & spiCmd === 3.U ){