diff --git a/a8000_protocol b/a8000_protocol
index 9ec492b..644059e 160000
--- a/a8000_protocol
+++ b/a8000_protocol
@@ -1 +1 @@
-Subproject commit 9ec492b5981174c6cc2db3dbfeeb6e9c68bc0a42
+Subproject commit 644059e79fd881d2a6c0d2f9b6ddc1098d9fabe4
diff --git a/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.cpp b/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.cpp
index 99e2432..1508db2 100644
--- a/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.cpp
+++ b/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.cpp
@@ -98,6 +98,7 @@ int32_t StepMotorCtrlModule::pri_module_xxx_reg(int32_t param_id, bool read, int
     PROCESS_REG(kreg_step_motor_pos, getnowpos(val), ACTION_NONE);
     PROCESS_REG(kreg_step_motor_is_enable, REG_GET(m_state.enable), ACTION_NONE);
     PROCESS_REG(kreg_step_motor_has_move_zero, REG_GET(m_state.has_move_to_zero), ACTION_NONE);
+    PROCESS_REG(kreg_step_motor_lost_step, REG_GET(m_state.lost_step), ACTION_NONE);
 
     PROCESS_REG(kreg_step_motor_dpos, REG_GET(m_state.dpos), ACTION_NONE);
     PROCESS_REG(kreg_step_motor_shaft, REG_GET(m_cfg.motor_shaft), REG_SET(m_cfg.motor_shaft));
@@ -253,6 +254,7 @@ void StepMotorCtrlModule::befor_motor_move() {  //
   getnowpos(m_state.before_move_pos);
   creg.module_status    = 1;
   creg.module_errorcode = 0;
+  m_state.lost_step     = 0;
   m_stepM1->enable(1);
 }
 void StepMotorCtrlModule::after_motor_move() {
@@ -295,7 +297,7 @@ bool StepMotorCtrlModule::check_when_run() {
     vPortExitCritical();
 
     int32_t dm1 = abs(m1enc - m1pos);
-
+    m_state.lost_step = dm1;
     if (m_cfg.pos_devi_tolerance != 0) {
       if (dm1 > m_cfg.pos_devi_tolerance) {
         ZLOGE(TAG, "motor pos devi %d", dm1);
@@ -704,8 +706,9 @@ int32_t StepMotorCtrlModule::do_step_motor_easy_move_to_io(int32_t ioindex, int3
 int32_t StepMotorCtrlModule::do_step_motor_easy_move_to_end_point() { return do_step_motor_easy_move_to_io(1, 1); }
 
 void StepMotorCtrlModule::checkdpos(int32_t expect_dpos) {
-  int32_t dpos = getnowpos() - m_state.before_move_pos;
-  if (m_cfg.pos_devi_tolerance != 0 && (abs(expect_dpos - dpos) > m_cfg.pos_devi_tolerance)) {
+  int32_t dpos      = getnowpos() - m_state.before_move_pos;
+  m_state.lost_step = expect_dpos - dpos;
+  if (m_cfg.pos_devi_tolerance != 0 && (abs(m_state.lost_step) > m_cfg.pos_devi_tolerance)) {
     ZLOGE(TAG, "check pos devi tolerance fail.... dpos%d,expectation_dpos:%d", dpos, expect_dpos);
     setErrorFlag(err::kstep_motor_lost_step);
   } else {
diff --git a/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.hpp b/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.hpp
index 0bd57c2..54d73b1 100644
--- a/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.hpp
+++ b/sdk/components/step_motor_ctrl_module/step_motor_ctrl_module.hpp
@@ -44,6 +44,7 @@ class StepMotorCtrlModule : public ZIModule {
     int32_t dpos;
     int32_t after_move_pos;
     int32_t before_move_pos;
+    int32_t lost_step;
     int32_t enable;
     int32_t debugmode;
     int32_t has_move_to_zero;
diff --git a/usrc/version.h b/usrc/version.h
index 3774596..5cdd200 100644
--- a/usrc/version.h
+++ b/usrc/version.h
@@ -1,2 +1,2 @@
 #pragma once
-#define PC_VERSION           1011
+#define PC_VERSION           1012