diff --git a/utilities/at32f421_freertos_demo/inc/TaskLoop.h b/utilities/at32f421_freertos_demo/inc/TaskLoop.h
index a807e6d..ea9fcc8 100644
--- a/utilities/at32f421_freertos_demo/inc/TaskLoop.h
+++ b/utilities/at32f421_freertos_demo/inc/TaskLoop.h
@@ -31,6 +31,12 @@
  *===========================================================================*/
 #define   ALFA_CAP1       79            // IIR 指数平滑 α = 79/256 ≈ 0.31
 
+/*===========================================================================
+ * 离开检测模式
+ *   1 = 平坦性三条件判定 (CN200910309382), 0 = 简单 cnt_release 防抖
+ *===========================================================================*/
+#define   USE_FLATNESS_EXIT   1
+
 /*===========================================================================
  * 频率测量参数
  * MEASUREMENT_BASE: 自适应测量窗口目标值 (≈131072)
@@ -85,6 +91,7 @@ extern uint8_t  g_loop_stable;            // 线圈数值已稳定 (0=稳定中,
 
 /* 离开防抖计数器（连续 CAPVD 恢复到阈值以上才释放） */
 extern uint8_t  loop1_cnt_release;        // 离开防抖计数
+#if USE_FLATNESS_EXIT
 extern uint8_t  g_exit_state;             // 离开检测: 0=追踪斜率, 1=等待平坦
 extern uint16_t g_max_slope;              // 第一上升坡面最大 |f'|
 extern uint16_t g_max_slope_rate;         // 第一上升坡面最大 |f''|
@@ -94,6 +101,7 @@ extern int32_t  g_prev_capvd;             // 上一帧 CAPVD (差分用)
 extern int32_t  g_prev_first_deriv;       // 上一帧一阶导数
 extern uint8_t  g_slope_flat_cnt;         // 斜率趋零连续计数
 extern uint8_t  g_flat_ok_cnt;            // 平坦条件满足连续计数
+#endif
 
 /*===========================================================================
  * 全局状态变量 — 计数器
diff --git a/utilities/at32f421_freertos_demo/src/TaskLoop.c b/utilities/at32f421_freertos_demo/src/TaskLoop.c
index 89f70bc..ced6631 100644
--- a/utilities/at32f421_freertos_demo/src/TaskLoop.c
+++ b/utilities/at32f421_freertos_demo/src/TaskLoop.c
@@ -52,6 +52,7 @@ uint8_t  loop1_FLAG_PLUSE;
 uint8_t  loop1_SensLevel;
 uint8_t  loop1_cnt_release;
 uint8_t  g_loop_stable;
+#if USE_FLATNESS_EXIT
 uint8_t  g_exit_state;
 uint16_t g_max_slope;
 uint16_t g_max_slope_rate;
@@ -61,6 +62,7 @@ int32_t  g_prev_capvd;
 int32_t  g_prev_first_deriv;
 uint8_t  g_slope_flat_cnt;
 uint8_t  g_flat_ok_cnt;
+#endif
 
 /*===========================================================================
  * 全局状态变量 — 计数器
@@ -332,6 +334,7 @@ void INIT_VD(void)
     loop1_FLAG_PLUSE = 0;
     loop1_cnt_release = 0;
     g_loop_stable     = 0;
+#if USE_FLATNESS_EXIT
     g_exit_state      = 0;
     g_max_slope       = 0;
     g_max_slope_rate  = 0;
@@ -341,6 +344,7 @@ void INIT_VD(void)
     g_prev_first_deriv = 0;
     g_slope_flat_cnt  = 0;
     g_flat_ok_cnt     = 0;
+#endif
 
     loop1_LC_HOLD  = 0;
     loop1_LC_Reset = 0;
@@ -552,9 +556,11 @@ void TMR15_GLOBAL_IRQHandler(void)
                     loop1_INI_LOOP  = 1;
                     loop1_LOOP_OK0  = 0;
                     g_loop_stable   = 0;
+#if USE_FLATNESS_EXIT
                     g_exit_state    = 0;
                     g_max_slope     = 0;
                     g_max_slope_rate = 0;
+#endif
                     LC_Hold_CNT     = 0;
                     loop1_ORG_CNT   = 0;
                     loop1_ORG_SUM   = 0;
@@ -675,6 +681,7 @@ void vd1_task(void)
             loop1_ORG_SUM = 0;
 
             /* 重置平坦性状态（专利 CN200910309382） */
+#if USE_FLATNESS_EXIT
             g_exit_state      = 0;   // 开始追踪第一上升坡面斜率
             g_max_slope       = 0;
             g_max_slope_rate  = 0;
@@ -682,61 +689,47 @@ void vd1_task(void)
             g_delta3          = 0;
             g_slope_flat_cnt  = 0;
             g_flat_ok_cnt     = 0;
+#endif
         }
     } else {
+#if USE_FLATNESS_EXIT
         /*================================================================
          * 有车状态 — 平坦性判定离开（专利 CN200910309382）
-         *
-         * Phase 1 (g_exit_state=0): 追踪第一上升坡面最大 |f'| 和 |f''|
-         * Phase 2 (g_exit_state=1): 三条件平坦性判定
-         *   |f-f_b| < Δ1  &&  |f'| < Δ2  &&  |f''| < Δ3
          *================================================================*/
-#define K1                  8       // 斜率除数
-#define K2                  8       // 斜率变化率除数
-#define SLOPE_FLAT_THRESH   100     // 斜率趋零阈值
-#define MIN_DELTA2          5       // Δ2 最小值
-#define MIN_DELTA3          2       // Δ3 最小值
-#define FLAT_CONFIRM_CNT    3       // 平坦连续确认次数
+#define K1                  8
+#define K2                  8
+#define SLOPE_FLAT_THRESH   100
+#define MIN_DELTA2          5
+#define MIN_DELTA3          2
+#define FLAT_CONFIRM_CNT    3
 
-        int32_t first_deriv;
-        int32_t abs_fd, abs_sd;
-        int32_t second_deriv;
+        int32_t first_deriv, abs_fd, abs_sd, second_deriv;
 
-        /* 计算一阶/二阶导数 */
         first_deriv  = (int32_t)loop1_CAPVD - g_prev_capvd;
         second_deriv = first_deriv - g_prev_first_deriv;
         abs_fd = (first_deriv >= 0) ? first_deriv : -first_deriv;
         abs_sd = (second_deriv >= 0) ? second_deriv : -second_deriv;
 
         if (g_exit_state == 0) {
-            /*--- Phase 1: 追踪第一上升坡面最大斜率 ---*/
             if (abs_fd > g_max_slope)      g_max_slope      = abs_fd;
             if (abs_sd > g_max_slope_rate) g_max_slope_rate = abs_sd;
-
-            /* 检测斜率是否已趋平坦 */
             if (abs_fd < SLOPE_FLAT_THRESH) {
                 g_slope_flat_cnt++;
                 if (g_slope_flat_cnt >= 3) {
-                    /* 计算动态阈值 Δ2, Δ3 */
                     g_delta2 = g_max_slope / K1;
                     g_delta3 = g_max_slope_rate / K2;
                     if (g_delta2 < MIN_DELTA2) g_delta2 = MIN_DELTA2;
                     if (g_delta3 < MIN_DELTA3) g_delta3 = MIN_DELTA3;
                     g_exit_state = 1;
                     g_flat_ok_cnt = 0;
-                    PRINT("FlatThresh: d2=%d d3=%d maxF'=%d maxF''=%d\n",
-                          g_delta2, g_delta3, g_max_slope, g_max_slope_rate);
                 }
             } else {
                 g_slope_flat_cnt = 0;
             }
         } else {
-            /*--- Phase 2: 平坦性三条件判定 ---*/
             int32_t dev = (int32_t)loop1_CAPVD - (int32_t)loop1_Origin;
-            int32_t cond1 = (dev >= 0) ? dev : -dev;     // |f - f_b|
-
+            int32_t cond1 = (dev >= 0) ? dev : -dev;
             loop1_dlt_ORG = ((uint32_t)loop1_Origin * SensTable_1[loop1_SensLevel]) >> 16;
-
             if (cond1 < (int32_t)loop1_dlt_ORG && abs_fd < (int32_t)g_delta2
                 && abs_sd < (int32_t)g_delta3) {
                 g_flat_ok_cnt++;
@@ -744,12 +737,10 @@ void vd1_task(void)
                     PRINT("Car_OFF_FLAT, CAPVD:%d Origin:%d d1:%d d2:%d d3:%d f':%d f'':%d\n",
                           loop1_CAPVD, loop1_Origin, loop1_dlt_ORG,
                           g_delta2, g_delta3, first_deriv, second_deriv);
-
                     loop1_VD_FLAG  = 0;
                     loop1_FLAG_OUT = 1;
                     loop1_VD_HOLD  = 0;
                     loop1_LC_HOLD  = 0;
-
                     loop1_ORG_CNT = 0;
                     loop1_ORG_SUM = 0;
                     Hold_CNT      = 0;
@@ -760,10 +751,32 @@ void vd1_task(void)
                 g_flat_ok_cnt = 0;
             }
         }
-
-        /* 保存历史用于下一帧差分 */
         g_prev_capvd       = loop1_CAPVD;
         g_prev_first_deriv = first_deriv;
+#else
+        /*================================================================
+         * 有车状态 — 简单 cnt_release 防抖离开
+         *================================================================*/
+        loop1_dlt_ORG = ((uint32_t)loop1_Origin * SensTable_1[loop1_SensLevel]) >> 16;
+
+        if ((loop1_Origin - loop1_dlt_ORG) < loop1_CAPVD) {
+            loop1_cnt_release++;
+            if (loop1_cnt_release >= 3) {
+                PRINT("Car_OFF, Value:%d CAPVD:%d Origin:%d dlt:%d\n",
+                      loop1_Value, loop1_CAPVD, loop1_Origin, loop1_dlt_ORG);
+                loop1_VD_FLAG  = 0;
+                loop1_FLAG_OUT = 1;
+                loop1_VD_HOLD  = 0;
+                loop1_LC_HOLD  = 0;
+                loop1_ORG_CNT = 0;
+                loop1_ORG_SUM = 0;
+                Hold_CNT      = 0;
+                loop1_cnt_release = 0;
+            }
+        } else {
+            if (loop1_cnt_release > 0) loop1_cnt_release = 0;
+        }
+#endif
     }
 }