diff --git a/.vscode/settings.json b/.vscode/settings.json
index 4bac2e4..798b888 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -5,6 +5,8 @@
         "tim.h": "c",
         "compare": "c",
         "type_traits": "c",
-        "gpio.h": "c"
+        "gpio.h": "c",
+        "stdint.h": "c",
+        "time.h": "c"
     }
 }
\ No newline at end of file
diff --git a/Core/App/app.c b/Core/App/app.c
index 49fdc9e..fa3b4bd 100644
--- a/Core/App/app.c
+++ b/Core/App/app.c
@@ -3,6 +3,7 @@
 #include "ui.h"
 #include "keypad.h"
 #include "global.h"
+#include "time.h"
 
 void app_init() {
     // 程序开始时执行一次
diff --git a/Core/Inc/time.h b/Core/Inc/time.h
new file mode 100644
index 0000000..4833b6f
--- /dev/null
+++ b/Core/Inc/time.h
@@ -0,0 +1,6 @@
+#pragma once
+#include <stdint.h>
+
+int32_t ticks_ms();
+int32_t ticks_add(int32_t t1, int32_t delta);
+int32_t ticks_diff(int32_t t1, int32_t t2);
diff --git a/Core/Src/time.c b/Core/Src/time.c
new file mode 100644
index 0000000..acf1a44
--- /dev/null
+++ b/Core/Src/time.c
@@ -0,0 +1,16 @@
+#include <stdint.h>
+#include "time.h"
+#include "main.h"
+
+int32_t ticks_ms() {
+    return HAL_GetTick() & INT32_MAX;
+}
+
+int32_t ticks_add(int32_t t1, int32_t delta) {
+    return (t1 + delta) & INT32_MAX;
+}
+
+int32_t ticks_diff(int32_t t1, int32_t t2) {
+    int32_t half = (INT32_MAX / 2) + 1;
+    return ((t1 - t2 + half) & INT32_MAX) - half;
+}
diff --git a/Makefile b/Makefile
index 8b63699..ee8735f 100644
--- a/Makefile
+++ b/Makefile
@@ -68,6 +68,7 @@ Core/Src/gpio.c \
 Core/Src/usart.c \
 Core/Src/spi.c \
 Core/Src/system_stm32g0xx.c \
+Core/Src/time.c \
 Core/App/app.c \
 Core/App/global.c \
 Core/Hardware/RotaryCoder/RotaryCoder.c	\