diff --git a/common.mk b/common.mk
index 62ac0ff7..9d58fa21 100644
--- a/common.mk
+++ b/common.mk
@@ -7,7 +7,7 @@ SRC +=	$(COMMON_DIR)/host.c \
 	$(COMMON_DIR)/action_layer.c \
 	$(COMMON_DIR)/action_util.c \
 	$(COMMON_DIR)/keymap.c \
-	$(COMMON_DIR)/timer.c \
+	$(COMMON_DIR)/avr/timer.c \
 	$(COMMON_DIR)/print.c \
 	$(COMMON_DIR)/bootloader.c \
 	$(COMMON_DIR)/suspend.c \
diff --git a/common/timer.c b/common/avr/timer.c
similarity index 98%
rename from common/timer.c
rename to common/avr/timer.c
index e0dec6ce..292b41c3 100644
--- a/common/timer.c
+++ b/common/avr/timer.c
@@ -18,6 +18,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <avr/io.h>
 #include <avr/interrupt.h>
 #include <stdint.h>
+#include "timer_avr.h"
 #include "timer.h"
 
 
diff --git a/common/mbed/timer.c b/common/mbed/timer.c
new file mode 100644
index 00000000..a64a7723
--- /dev/null
+++ b/common/mbed/timer.c
@@ -0,0 +1,40 @@
+#include "cmsis.h"
+#include "timer.h"
+
+/* Mill second tick count */
+volatile uint32_t timer_count = 0;
+
+/* Timer interrupt handler */
+void SysTick_Handler(void)  {
+    timer_count++;
+}
+
+void timer_init(void)
+{
+    SysTick_Config(SystemCoreClock / 1000); /* 1ms tick */
+}
+
+void timer_clear(void)
+{
+    timer_count = 0;
+}
+
+uint16_t timer_read(void)
+{
+    return (uint16_t)(timer_count & 0xFFFF);
+}
+
+uint32_t timer_read32(void)
+{
+    return timer_count;
+}
+
+uint16_t timer_elapsed(uint16_t last)
+{
+    return TIMER_DIFF_16(timer_read(), last);
+}
+
+uint32_t timer_elapsed32(uint32_t last)
+{
+    return TIMER_DIFF_32(timer_read32(), last);
+}
diff --git a/common/timer.h b/common/timer.h
index 6437473f..f0c5ffc9 100644
--- a/common/timer.h
+++ b/common/timer.h
@@ -20,25 +20,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <stdint.h>
 
-#ifndef TIMER_PRESCALER
-#   if F_CPU > 16000000
-#       define TIMER_PRESCALER      256
-#   elif F_CPU > 2000000
-#       define TIMER_PRESCALER      64
-#   elif F_CPU > 250000
-#       define TIMER_PRESCALER      8
-#   else
-#       define TIMER_PRESCALER      1
-#   endif
-#endif
-#define TIMER_RAW_FREQ      (F_CPU/TIMER_PRESCALER)
-#define TIMER_RAW           TCNT0
-#define TIMER_RAW_TOP       (TIMER_RAW_FREQ/1000)
-
-#if (TIMER_RAW_TOP > 255)
-#   error "Timer0 can't count 1ms at this clock freq. Use larger prescaler."
-#endif
-
 #define TIMER_DIFF(a, b, max)   ((a) >= (b) ?  (a) - (b) : (max) - (b) + (a))
 #define TIMER_DIFF_8(a, b)      TIMER_DIFF(a, b, UINT8_MAX)
 #define TIMER_DIFF_16(a, b)     TIMER_DIFF(a, b, UINT16_MAX)
diff --git a/keyboard/mbed_onekey/common.mk b/keyboard/mbed_onekey/common.mk
index f21fce88..975ae9d0 100644
--- a/keyboard/mbed_onekey/common.mk
+++ b/keyboard/mbed_onekey/common.mk
@@ -1,19 +1,20 @@
 COMMON_DIR = common
 OBJECTS += \
-#	$(COMMON_DIR)/host.o \
-#	$(COMMON_DIR)/keyboard.o \
-#	$(COMMON_DIR)/action.o \
-#	$(COMMON_DIR)/action_tapping.o \
-#	$(COMMON_DIR)/action_macro.o \
-#	$(COMMON_DIR)/action_layer.o \
-#	$(COMMON_DIR)/action_util.o \
-#	$(COMMON_DIR)/keymap.o \
-#	$(COMMON_DIR)/timer.o \
-	$(COMMON_DIR)/print.o \
-#	$(COMMON_DIR)/bootloader.o \
-#	$(COMMON_DIR)/suspend.o \
-	$(COMMON_DIR)/xprintf.o \
-	$(COMMON_DIR)/util.o
+	$(OBJDIR)/$(COMMON_DIR)/mbed/timer.o \
 
 INCLUDE_PATHS += \
 	-I$(TMK_DIR)/$(COMMON_DIR)
+
+
+
+
+#	$(OBJDIR)/$(COMMON_DIR)/host.o \
+#	$(OBJDIR)/$(COMMON_DIR)/keyboard.o \
+#	$(OBJDIR)/$(COMMON_DIR)/action.o \
+#	$(OBJDIR)/$(COMMON_DIR)/action_tapping.o \
+#	$(OBJDIR)/$(COMMON_DIR)/action_macro.o \
+#	$(OBJDIR)/$(COMMON_DIR)/action_layer.o \
+#	$(OBJDIR)/$(COMMON_DIR)/action_util.o \
+#	$(OBJDIR)/$(COMMON_DIR)/keymap.o \
+#	$(OBJDIR)/$(COMMON_DIR)/bootloader.o \
+#	$(OBJDIR)/$(COMMON_DIR)/suspend.o \
diff --git a/keyboard/mbed_onekey/main.cpp b/keyboard/mbed_onekey/main.cpp
index 581534e0..1df940aa 100644
--- a/keyboard/mbed_onekey/main.cpp
+++ b/keyboard/mbed_onekey/main.cpp
@@ -1,6 +1,7 @@
 #include "mbed.h"
 #include "HIDKeyboard.h"
 #include "debug.h"
+#include "timer.h"
  
 /*
 //#define DEBUG 
@@ -27,11 +28,16 @@ int main(void) {
     //led_red = 0;
     //led_green = 0;
     debug_enable = true;
-    dprintf("HIDKeyboard:\n");
-    print("aaa");
+    dprintf("HIDKeyboard:\r\n");
+
+    timer_init();
+    xprintf("timer: %i\r\n", timer_read());
 
     report_keyboard_t report = { 2, 0, 4, }; //a
     report_keyboard_t report_off = { 0 };
+
+    bool last_isp = isp;
+    uint32_t last_timer;
     while (1) {
         //keyboard.mediaControl(KEY_VOLUME_DOWN);
         //keyboard.printf("Hello World from Mbed\r\n");
@@ -42,14 +48,19 @@ int main(void) {
         //leds = keyboard.lockStatus();
         //ser.putc(ser.getc());
 
+        if (last_isp == isp) continue;
         if (isp == 0) {
             led_red = 0;    // on
-            keyboard.sendReport(report);
+    xprintf("timer: %i\r\n", timer_read32());
+    xprintf("diff: %i\r\n", timer_elapsed32(last_timer));
+            //keyboard.sendReport(report);
         } else {
             led_red = 1;    // off
-            keyboard.sendReport(report_off);
+            //keyboard.sendReport(report_off);
         }
-        led_green = !led_green;
+        last_isp = isp;
+        last_timer = timer_read();
+        //led_green = !led_green;
         //wait(0.5);
     }
 }