diff --git a/Peripheral/Inc/led.h b/Peripheral/Inc/led.h
index 2ca5903..17ef10a 100644
--- a/Peripheral/Inc/led.h
+++ b/Peripheral/Inc/led.h
@@ -11,10 +11,6 @@
 void LED_Start(uint8_t led);
 void LED_Stop(uint8_t led);
 
-
-void LED_StartTimed(uint8_t led, uint16_t time);
-void LED_StartNTimes(uint8_t led, uint16_t on_time, uint16_t off_time);
-
 // duty in [0, 255]
 void LED_SetDuty(uint8_t r, uint8_t g, uint8_t b);
 
diff --git a/Service/Inc/timer.h b/Service/Inc/timer.h
index 60f4dff..769404c 100644
--- a/Service/Inc/timer.h
+++ b/Service/Inc/timer.h
@@ -14,10 +14,7 @@
 #define EVENT_MAX 8
 
 void TIMER_Init(void);
-int8_t TIMER_AddInfiniteLoopEvent(int8_t id, void (*func)(void), uint16_t loop_time);
-int8_t TIMER_AddFiniteLoopEvent(int8_t id, void (*func)(void), uint16_t loop_time, uint16_t loop_cnt);
-int8_t TIMER_AddFiniteLoopEventWithParam(int8_t event_id, void (*func)(uint16_t param), uint16_t loop_time, uint16_t loop_cnt, uint16_t param);
-int8_t TIMER_AddDelayEvent(int8_t id, void (*func)(void), uint16_t delay_time);
-void TIMER_DelLoopEvent(int8_t id);
+void TIMER_AddLoopEvent(uint8_t type, void (*func)(void), uint16_t loop_time);
+void TIMER_DelLoopEvent(uint8_t type);
 
 #endif
diff --git a/Service/Src/timer.c b/Service/Src/timer.c
index e9f695d..ecec7f7 100644
--- a/Service/Src/timer.c
+++ b/Service/Src/timer.c
@@ -1,35 +1,22 @@
 #include "timer.h"
-
-#include <math.h>
-
 #include "tim.h"
-
-typedef enum
-{
-    INFINITE_LOOP_EVENT, // 无限循环事件
-    FINITE_LOOP_EVENT,   // 有限循环事件
-    FINITE_LOOP_EVENT_WITH_PARAM,
-    DELAY_EVENT // 延迟事件
-} EventType;
+#include <math.h>
 
 typedef struct Event
 {
-    uint8_t id;
     void (*func)(void);
-    void (*param_func)(uint16_t);
     uint16_t time;
-    EventType type;
     uint8_t enabled;
-    uint16_t loop_cnt;
-    uint32_t begin_time;
-    uint16_t param;
 } Event;
 
 static Event event[EVENT_MAX];
-static int event_cnt;
-static uint32_t current_time;
+static uint32_t time_cnt;
+static uint32_t time_lcm = 1;
 
-void TIMER_Count(TIM_HandleTypeDef *htim);
+uint32_t gcd(uint32_t a, uint32_t b);
+uint32_t lcm(uint32_t a, uint32_t b);
+
+void TIMER_Count(void);
 
 void TIMER_Init(void)
 {
@@ -37,124 +24,41 @@ void TIMER_Init(void)
     HAL_TIM_Base_Start_IT(&htim4);
 }
 
-/// @brief 注册无限循环定时回调事件
+/// @brief 注册定时回调事件
 /// @param func 回调函数 void func(void)
 /// @param loop_time 定时时间，单位毫秒
-int8_t TIMER_AddInfiniteLoopEvent(int8_t event_id, void (*func)(void), uint16_t loop_time)
+void TIMER_AddLoopEvent(uint8_t type, void (*func)(void), uint16_t loop_time)
 {
-    if (event_id == -1) event_id = event_cnt++;
-    event[event_id].type = INFINITE_LOOP_EVENT;
-    event[event_id].id = event_id;
-    event[event_id].func = func;
-    event[event_id].time = loop_time;
-    event[event_id].begin_time = current_time;
-    event[event_id].enabled = 1;
-    return event_id;
+    event[type].func = func;
+    event[type].time = loop_time;
+    event[type].enabled = 1;
+    time_lcm = lcm(time_lcm, loop_time);
 }
 
-/// @brief 注册有限循环定时回调事件
-/// @param func 回调函数 void func(void)
-/// @param loop_time 定时时间，单位毫秒
-/// @param loop_cnt 循环次数
-int8_t TIMER_AddFiniteLoopEventWithParam(int8_t event_id, void (*func)(uint16_t param), uint16_t loop_time, uint16_t loop_cnt, uint16_t param)
+void TIMER_DelLoopEvent(uint8_t type)
 {
-    if (event_id == -1) event_id = event_cnt++;
-    event[event_id].type = FINITE_LOOP_EVENT_WITH_PARAM;
-    event[event_id].id = event_id;
-    event[event_id].param_func = func;
-    event[event_id].time = loop_time;
-    event[event_id].begin_time = current_time;
-    event[event_id].enabled = 1;
-    event[event_id].param = param;
-    event[event_id].loop_cnt = loop_cnt;
-    return event_id;
+    event[type].enabled = 0;
+    time_lcm /= event[type].time;
 }
 
-int8_t TIMER_AddFiniteLoopEvent(int8_t event_id, void (*func)(void), uint16_t loop_time, uint16_t loop_cnt)
+void TIMER_Count(void)
 {
-    if (event_id == -1) event_id = event_cnt++;
-    event[event_id].type = FINITE_LOOP_EVENT;
-    event[event_id].id = event_id;
-    event[event_id].func = func;
-    event[event_id].time = loop_time;
-    event[event_id].begin_time = current_time;
-    event[event_id].enabled = 1;
-    event[event_id].loop_cnt = loop_cnt;
-    return event_id;
+    ++time_cnt;
+    for (uint8_t i = 0; i < EVENT_MAX; ++i)
+        if (event[i].enabled && time_cnt % event[i].time == 0)
+            event[i].func();
+    if (time_cnt == time_lcm)
+        time_cnt = 0;
 }
 
-/// @brief 注册延迟定时回调事件（单次）
-/// @param func 回调函数 void func(void)
-/// @param loop_time 定时时间，单位毫秒
-int8_t TIMER_AddDelayEvent(int8_t event_id, void (*func)(void), uint16_t delay_time)
+uint32_t gcd(uint32_t a, uint32_t b)
 {
-    if (event_id == -1) event_id = event_cnt++;
-    event[event_id].type = DELAY_EVENT;
-    event[event_id].id = event_id;
-    event[event_id].func = func;
-    event[event_id].time = delay_time;
-    event[event_id].begin_time = current_time;
-    event[event_id].enabled = 1;
-    return event_id;
+    if (b == 0)
+        return a;
+    return gcd(b, a % b);
 }
 
-void TIMER_DelLoopEvent(int8_t id)
+uint32_t lcm(uint32_t a, uint32_t b)
 {
-    event[id].enabled = 0;
-}
-
-void TIMER_Count(TIM_HandleTypeDef *htim)
-{
-    ++current_time;
-    for (uint8_t i = 0; i < event_cnt; ++i)
-    {
-        if (event[i].enabled == 0)
-            continue;
-
-        switch (event[i].type)
-        {
-            case INFINITE_LOOP_EVENT: // 无限循环事件
-                if ((current_time - event[i].begin_time) % event[i].time == 0)
-                {
-                    event[i].func();
-                }
-                break;
-            case FINITE_LOOP_EVENT: // 有限循环事件
-                if ((current_time - event[i].begin_time) % event[i].time == 0)
-                {
-                    event[i].func();
-                    if (event[i].loop_cnt-- <= 0)
-                    {
-                        TIMER_DelLoopEvent(event[i].id);
-                    }
-                }
-                break;
-            case FINITE_LOOP_EVENT_WITH_PARAM:
-                if ((current_time - event[i].begin_time) % event[i].time == 0)
-                {
-                    printf("FINITE_LOOP_EVENT_WITH_PARAM %d, %d, %d\n",
-                           current_time, event[i].begin_time, event[i].time);
-                    event[i].param_func(event[i].param);
-                    if (--event[i].loop_cnt <= 0)
-                    {
-                        printf("remove FINITE_LOOP_EVENT_WITH_PARAM %d, %d, %d\n",
-                               current_time, event[i].begin_time, event[i].time);
-                        TIMER_DelLoopEvent(event[i].id);
-                    }
-                }
-                break;
-            case DELAY_EVENT: // 延迟事件
-                if (current_time > event[i].begin_time &&
-                    (current_time - event[i].begin_time) % event[i].time == 0)
-                {
-                    event[i].func();
-                    printf("DELAY_EVENT %d, %d, %d\n",
-                           current_time, event[i].begin_time, event[i].time);
-                    TIMER_DelLoopEvent(event[i].id);
-                }
-                break;
-            default:
-                break;
-        }
-    }
+    return a / gcd(a, b) * b;
 }