diff --git a/Doxyfile b/Doxyfile
index 5fba638..2685234 100644
--- a/Doxyfile
+++ b/Doxyfile
@@ -38,7 +38,7 @@ PROJECT_NAME           = perf_counter
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = v2.2.0
+PROJECT_NUMBER         = v2.2.1
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/GorgonMeducer.perf_counter.pdsc b/GorgonMeducer.perf_counter.pdsc
index eec3657..88cce4c 100644
--- a/GorgonMeducer.perf_counter.pdsc
+++ b/GorgonMeducer.perf_counter.pdsc
@@ -16,6 +16,9 @@
   <repository type="git">https://github.com/GorgonMeducer/perf_counter.git</repository>
   
   <releases>
+    <release date="2023-05-19" version="2.2.1" url="https://raw.githubusercontent.com/GorgonMeducer/perf_counter/CMSIS-Pack/cmsis-pack/GorgonMeducer.perf_counter.2.2.1.pack">
+      - Update perfc_is_time_out_ms and perf_is_time_out_us
+    </release>
     <release date="2023-05-18" version="2.2.0" url="https://raw.githubusercontent.com/GorgonMeducer/perf_counter/CMSIS-Pack/cmsis-pack/GorgonMeducer.perf_counter.2.2.0.pack">
       - Enhance Timer Services
       - Other minor changes
@@ -234,7 +237,7 @@
   -->
 
     <components>
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="Core" Cvariant="Library" condition="CMSIS-CORE">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="Core" Cvariant="Library" condition="CMSIS-CORE">
               <description>A dedicated performance counter for Cortex-M systick.</description>
               <files>
                 <file category="header"     name="lib/perf_counter.h"/>
@@ -252,7 +255,7 @@
 #define __PERF_COUNTER_CFG_USE_SYSTICK_WRAPPER__ 1
               </Pre_Include_Global_h>
             </component>
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="Core" Cvariant="Source" isDefaultVariant="true" condition="CMSIS-CORE">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="Core" Cvariant="Source" isDefaultVariant="true" condition="CMSIS-CORE">
               <description>A dedicated performance counter for Cortex-M systick.</description>
               <files>
                 <file category="header"     name="lib/perf_counter.h"/>
@@ -295,7 +298,7 @@
               </Pre_Include_Global_h>
             </component>
 
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="RTX5 Patch" condition="RTX5 Patch">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="RTX5 Patch" condition="RTX5 Patch">
               <description>A Patch for RTX5</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_rtx5.c"/>
@@ -307,7 +310,7 @@
               </Pre_Include_Global_h>
             </component>
 
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="FreeRTOS Patch" condition="perf_counter">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="FreeRTOS Patch" condition="perf_counter">
               <description>A Patch for FreeRTOS</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_freertos.c"/>
@@ -330,7 +333,7 @@ extern void __freertos_evr_on_task_switched_in(void *ptTCB, unsigned int uxTopPr
               </Pre_Include_Global_h>
             </component>
             
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="RT-Thread Patch" condition="perf_counter">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="RT-Thread Patch" condition="perf_counter">
               <description>A Patch for RT-Thread</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_rt_thread.c"/>
@@ -348,7 +351,7 @@ extern void __rt_thread_scheduler_hook(struct rt_thread *from, struct rt_thread
               </Pre_Include_Global_h>
             </component>
             
-            <component Cclass="Utilities" Cversion="2.1.0" Cgroup="perf_counter" Csub="ThreadX Patch" condition="perf_counter">
+            <component Cclass="Utilities" Cversion="2.1.1" Cgroup="perf_counter" Csub="ThreadX Patch" condition="perf_counter">
               <description>A Patch for ThreadX</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_threadx.c"/>
diff --git a/README.md b/README.md
index 21186ac..74f3128 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# perf_counter (v2.2.0)
+# perf_counter (v2.2.1)
 A dedicated performance counter for Cortex-M Systick. It shares the SysTick with users' original SysTick function(s) without interfering with it. This library will bring new functionalities, such as performance counter,` delay_us` and `clock()` service defined in `time.h`.
 
 ### Features:
diff --git a/cmsis-pack/GorgonMeducer.perf_counter.2.2.0.pack b/cmsis-pack/GorgonMeducer.perf_counter.2.2.1.pack
similarity index 84%
rename from cmsis-pack/GorgonMeducer.perf_counter.2.2.0.pack
rename to cmsis-pack/GorgonMeducer.perf_counter.2.2.1.pack
index ee97f8e..75baf9e 100644
Binary files a/cmsis-pack/GorgonMeducer.perf_counter.2.2.0.pack and b/cmsis-pack/GorgonMeducer.perf_counter.2.2.1.pack differ
diff --git a/cmsis-pack/GorgonMeducer.perf_counter.pdsc b/cmsis-pack/GorgonMeducer.perf_counter.pdsc
index eec3657..88cce4c 100644
--- a/cmsis-pack/GorgonMeducer.perf_counter.pdsc
+++ b/cmsis-pack/GorgonMeducer.perf_counter.pdsc
@@ -16,6 +16,9 @@
   <repository type="git">https://github.com/GorgonMeducer/perf_counter.git</repository>
   
   <releases>
+    <release date="2023-05-19" version="2.2.1" url="https://raw.githubusercontent.com/GorgonMeducer/perf_counter/CMSIS-Pack/cmsis-pack/GorgonMeducer.perf_counter.2.2.1.pack">
+      - Update perfc_is_time_out_ms and perf_is_time_out_us
+    </release>
     <release date="2023-05-18" version="2.2.0" url="https://raw.githubusercontent.com/GorgonMeducer/perf_counter/CMSIS-Pack/cmsis-pack/GorgonMeducer.perf_counter.2.2.0.pack">
       - Enhance Timer Services
       - Other minor changes
@@ -234,7 +237,7 @@
   -->
 
     <components>
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="Core" Cvariant="Library" condition="CMSIS-CORE">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="Core" Cvariant="Library" condition="CMSIS-CORE">
               <description>A dedicated performance counter for Cortex-M systick.</description>
               <files>
                 <file category="header"     name="lib/perf_counter.h"/>
@@ -252,7 +255,7 @@
 #define __PERF_COUNTER_CFG_USE_SYSTICK_WRAPPER__ 1
               </Pre_Include_Global_h>
             </component>
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="Core" Cvariant="Source" isDefaultVariant="true" condition="CMSIS-CORE">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="Core" Cvariant="Source" isDefaultVariant="true" condition="CMSIS-CORE">
               <description>A dedicated performance counter for Cortex-M systick.</description>
               <files>
                 <file category="header"     name="lib/perf_counter.h"/>
@@ -295,7 +298,7 @@
               </Pre_Include_Global_h>
             </component>
 
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="RTX5 Patch" condition="RTX5 Patch">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="RTX5 Patch" condition="RTX5 Patch">
               <description>A Patch for RTX5</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_rtx5.c"/>
@@ -307,7 +310,7 @@
               </Pre_Include_Global_h>
             </component>
 
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="FreeRTOS Patch" condition="perf_counter">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="FreeRTOS Patch" condition="perf_counter">
               <description>A Patch for FreeRTOS</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_freertos.c"/>
@@ -330,7 +333,7 @@ extern void __freertos_evr_on_task_switched_in(void *ptTCB, unsigned int uxTopPr
               </Pre_Include_Global_h>
             </component>
             
-            <component Cclass="Utilities" Cversion="2.2.0" Cgroup="perf_counter" Csub="RT-Thread Patch" condition="perf_counter">
+            <component Cclass="Utilities" Cversion="2.2.1" Cgroup="perf_counter" Csub="RT-Thread Patch" condition="perf_counter">
               <description>A Patch for RT-Thread</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_rt_thread.c"/>
@@ -348,7 +351,7 @@ extern void __rt_thread_scheduler_hook(struct rt_thread *from, struct rt_thread
               </Pre_Include_Global_h>
             </component>
             
-            <component Cclass="Utilities" Cversion="2.1.0" Cgroup="perf_counter" Csub="ThreadX Patch" condition="perf_counter">
+            <component Cclass="Utilities" Cversion="2.1.1" Cgroup="perf_counter" Csub="ThreadX Patch" condition="perf_counter">
               <description>A Patch for ThreadX</description>
               <files>
                 <file category="source"     name="lib/perf_os_patch_threadx.c"/>
diff --git a/example/example.uvoptx b/example/example.uvoptx
index 310ac4b..75e7724 100644
--- a/example/example.uvoptx
+++ b/example/example.uvoptx
@@ -75,7 +75,7 @@
       <OPTFL>
         <tvExp>1</tvExp>
         <tvExpOptDlg>0</tvExpOptDlg>
-        <IsCurrentTarget>1</IsCurrentTarget>
+        <IsCurrentTarget>0</IsCurrentTarget>
       </OPTFL>
       <CpuCode>7</CpuCode>
       <DebugOpt>
@@ -297,7 +297,7 @@
       <OPTFL>
         <tvExp>1</tvExp>
         <tvExpOptDlg>0</tvExpOptDlg>
-        <IsCurrentTarget>0</IsCurrentTarget>
+        <IsCurrentTarget>1</IsCurrentTarget>
       </OPTFL>
       <CpuCode>7</CpuCode>
       <DebugOpt>
diff --git a/lib/libperf_counter_gcc.a b/lib/libperf_counter_gcc.a
index 1296202..d1eb553 100644
Binary files a/lib/libperf_counter_gcc.a and b/lib/libperf_counter_gcc.a differ
diff --git a/lib/perf_counter.h b/lib/perf_counter.h
index 1b9c631..bf3ca37 100644
--- a/lib/perf_counter.h
+++ b/lib/perf_counter.h
@@ -397,7 +397,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] __timestamp_ptr an optional timestamp holder
  * \param[in] __auto_reload whether starting next period after a timeout event
  *
@@ -411,7 +411,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] __timestamp_ptr an optional timestamp holder
  *
  * \return bool whether it is timeout
@@ -423,7 +423,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] __timestamp_ptr an optional timestamp holder
  *
  * \return bool whether it is timeout
@@ -434,7 +434,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] ... an optional timestamp holder
  * \param[in] ... an optional indicator for whether starting next period after a timeout event
  *
diff --git a/lib/perf_counter.lib b/lib/perf_counter.lib
index 96f7b42..df6706b 100644
Binary files a/lib/perf_counter.lib and b/lib/perf_counter.lib differ
diff --git a/perf_counter.h b/perf_counter.h
index 1b9c631..bf3ca37 100644
--- a/perf_counter.h
+++ b/perf_counter.h
@@ -397,7 +397,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] __timestamp_ptr an optional timestamp holder
  * \param[in] __auto_reload whether starting next period after a timeout event
  *
@@ -411,7 +411,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] __timestamp_ptr an optional timestamp holder
  *
  * \return bool whether it is timeout
@@ -423,7 +423,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] __timestamp_ptr an optional timestamp holder
  *
  * \return bool whether it is timeout
@@ -434,7 +434,7 @@ __asm(".global __ensure_systick_wrapper\n\t");
 /*!
  * \brief set an alarm with given period in us and check the status
  *
- * \param[in] __ms a time period in microsecond
+ * \param[in] __us a time period in microsecond
  * \param[in] ... an optional timestamp holder
  * \param[in] ... an optional indicator for whether starting next period after a timeout event
  *