diff --git a/.gitignore b/.gitignore
index 167bed0..4a9aa90 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.vscode
 *.o
 *.out 
 test
diff --git a/MultiTimer.c b/MultiTimer.c
index f0419fb..947e35e 100644
--- a/MultiTimer.c
+++ b/MultiTimer.c
@@ -1,11 +1,6 @@
 #include "MultiTimer.h"
 #include <stdio.h>
 
-#define MULTIMER_MAX_TIMEOUT  0x7fffffff
-
-/* Check if timer's expiry time is greater than time and care about uint32_t wraparounds */
-#define CHECK_TIME_LESS_THAN(t, compare_to) ( (((uint32_t)((t)-(compare_to))) > MULTIMER_MAX_TIMEOUT) ? 1 : 0 )
-
 /* Timer handle list head. */
 static MultiTimer* timerList = NULL;
 
@@ -18,9 +13,9 @@ int MultiTimerInstall(PlatformTicksFunction_t ticksFunc)
     return 0;
 }
 
-int MultiTimerStart(MultiTimer* timer, uint32_t timing, MultiTimerCallback_t callback, void* userData)
+int MultiTimerStart(MultiTimer* timer, uint64_t timing, MultiTimerCallback_t callback, void* userData)
 {
-    if (!timer || !callback || timing > MULTIMER_MAX_TIMEOUT / 2 ) {
+    if (!timer || !callback ) {
         return -1;
     }
     MultiTimer** nextTimer = &timerList;
@@ -72,7 +67,7 @@ int MultiTimerYield(void)
     MultiTimer* entry = timerList;
     for (; entry; entry = entry->next) {
         /* Sorted list, just process with the front part. */
-        if (CHECK_TIME_LESS_THAN(platformTicksFunction(), entry->deadline)) {
+        if (platformTicksFunction() < entry->deadline) {
             return (int)(entry->deadline - platformTicksFunction());
         }
         /* remove expired timer from list */
@@ -83,4 +78,5 @@ int MultiTimerYield(void)
             entry->callback(entry, entry->userData);
         }
     }
+    return 0;
 }
diff --git a/MultiTimer.h b/MultiTimer.h
index 3ae6671..a36fd0f 100644
--- a/MultiTimer.h
+++ b/MultiTimer.h
@@ -29,7 +29,7 @@
 extern "C" {  
 #endif
 
-typedef uint32_t (*PlatformTicksFunction_t)(void);
+typedef uint64_t (*PlatformTicksFunction_t)(void);
 
 typedef struct MultiTimerHandle MultiTimer;
 
@@ -37,7 +37,7 @@ typedef void (*MultiTimerCallback_t)(MultiTimer* timer, void* userData);
 
 struct MultiTimerHandle {
     MultiTimer* next;
-    uint32_t deadline;
+    uint64_t deadline;
     MultiTimerCallback_t callback;
     void* userData;
 };
@@ -59,7 +59,7 @@ int MultiTimerInstall(PlatformTicksFunction_t ticksFunc);
  * @param userData user data.
  * @return int 0: success, -1: fail.
  */
-int MultiTimerStart(MultiTimer* timer, uint32_t timing, MultiTimerCallback_t callback, void* userData);
+int MultiTimerStart(MultiTimer* timer, uint64_t timing, MultiTimerCallback_t callback, void* userData);
 
 /**
  * @brief Stop the timer work, remove the handle off work list.
diff --git a/README.md b/README.md
index 907c181..2e61bdf 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ MultiTimer 是一个软件定时器扩展模块，可无限扩展你所需的定
 1. 配置系统时间基准接口，安装定时器驱动；
 
 ```c
-uint32_t PlatformTicksGetFunc(void)
+uint64_t PlatformTicksGetFunc(void)
 {
     /* Platform implementation */
 }
@@ -24,7 +24,7 @@ MultiTimer timer1;
 3. 设置定时时间，超时回调处理函数， 用户上下指针，启动定时器；
 
 ```c
-int MultiTimerStart(&timer1, uint32_t timing, MultiTimerCallback_t callback, void* userData);
+int MultiTimerStart(&timer1, uint64_t timing, MultiTimerCallback_t callback, void* userData);
 ```
 
 4. 在主循环调用定时器后台处理函数
@@ -43,11 +43,9 @@ int main(int argc, char *argv[])
 ## 功能限制
 1.定时器的时钟频率直接影响定时器的精确度，尽可能采用1ms/5ms/10ms这几个精度较高的tick;
 
-2.定义应用定时器时，最大定时不可以超过 UINT32_MAX / 4；
+2.定时器的回调函数内不应执行耗时操作，否则可能因占用过长的时间，导致其他定时器无法正常超时；
 
-3.定时器的回调函数内不应执行耗时操作，否则可能因占用过长的时间，导致其他定时器无法正常超时；
-
-4.由于定时器的回调函数是在 MultiTimerYield 内执行的，需要注意栈空间的使用不能过大，否则可能会导致栈溢出。
+3.由于定时器的回调函数是在 MultiTimerYield 内执行的，需要注意栈空间的使用不能过大，否则可能会导致栈溢出。
 
 ## Examples
 
@@ -63,11 +61,11 @@ MultiTimer timer1;
 MultiTimer timer2;
 MultiTimer timer3;
 
-uint32_t PlatformTicksGetFunc(void)
+uint64_t PlatformTicksGetFunc(void)
 {
     struct timespec current_time;
     clock_gettime(CLOCK_MONOTONIC, &current_time);
-    return (uint32_t)((current_time.tv_sec * 1000) + (current_time.tv_nsec / 1000000));
+    return (uint64_t)((current_time.tv_sec * 1000) + (current_time.tv_nsec / 1000000));
 }
 
 void exampleTimer1Callback(MultiTimer* timer, void *userData)
diff --git a/examples/test_linux.c b/examples/test_linux.c
index d945b34..9b91182 100644
--- a/examples/test_linux.c
+++ b/examples/test_linux.c
@@ -7,27 +7,27 @@ MultiTimer timer1;
 MultiTimer timer2;
 MultiTimer timer3;
 
-uint32_t PlatformTicksGetFunc(void)
+uint64_t PlatformTicksGetFunc(void)
 {
     struct timespec current_time;
     clock_gettime(CLOCK_MONOTONIC, &current_time);
-    return (uint32_t)((current_time.tv_sec * 1000) + (current_time.tv_nsec / 1000000));
+    return (uint64_t)((current_time.tv_sec * 1000) + (current_time.tv_nsec / 1000000));
 }
 
 void exampleTimer1Callback(MultiTimer* timer, void *userData)
 {
-    printf("[T:%010d] Timer:%p callback-> %s.\r\n", PlatformTicksGetFunc(), timer, (char*)userData);
+    printf("[%012ld] Timer:%p callback-> %s.\r\n", PlatformTicksGetFunc(), timer, (char*)userData);
     MultiTimerStart(timer, 1000, exampleTimer1Callback, userData);
 }
 
 void exampleTimer2Callback(MultiTimer* timer, void *userData)
 {
-    printf("[T:%010d] Timer:%p callback-> %s.\r\n", PlatformTicksGetFunc(), timer, (char*)userData);
+    printf("[%012ld] Timer:%p callback-> %s.\r\n", PlatformTicksGetFunc(), timer, (char*)userData);
 }
 
 void exampleTimer3Callback(MultiTimer* timer, void *userData)
 {
-    printf("[T:%010d] Timer:%p callback-> %s.\r\n", PlatformTicksGetFunc(), timer, (char*)userData);
+    printf("[%012ld] Timer:%p callback-> %s.\r\n", PlatformTicksGetFunc(), timer, (char*)userData);
     MultiTimerStart(timer, 4567, exampleTimer3Callback, userData);
 }