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diff --git a/docs/zh_CN/unit/joystick.md b/docs/zh_CN/unit/joystick.md
index d14a46a4..15f5ca9e 100644
--- a/docs/zh_CN/unit/joystick.md
+++ b/docs/zh_CN/unit/joystick.md
@@ -10,7 +10,7 @@
 
 ## 描述
 
-**<mark>Joystick</mark>**是一款内置MEGA328芯片控制的摇杆模块，可以输出X-Y两个方向的摇杆偏移量，可以判断Z方向是否按下的。
+**<mark>Joystick</mark>** 是一款内置MEGA328芯片控制的摇杆模块，可以输出X-Y两个方向的摇杆偏移量，可以判断Z方向是否按下的。
 
 内部电路里，摇杆的X方向与MEGA328的A0管脚相连，Y方向与MEGA328的A1管脚相连，Z方向与MEGA的A2管脚相连。
 
diff --git a/docs/zh_CN/unit/trace.md b/docs/zh_CN/unit/trace.md
index e69de29b..2893ed57 100644
--- a/docs/zh_CN/unit/trace.md
+++ b/docs/zh_CN/unit/trace.md
@@ -0,0 +1,81 @@
+# TRACE - 巡线 Unit {docsify-ignore-all}
+
+<img src="assets/img/product_pics/unit/unit_trace_01.png" width="30%" height="30%">
+
+***
+
+:memo:**[描述](#描述)**&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;:octocat:**[例程](#例程)**&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;:electric_plug:**[原理图](#原理图)**&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;🛒**[购买链接](https://item.taobao.com/item.htm?spm=a1z10.3-c.w4002-1172588106.12.4c32425eGaqxO8&id=587199991600)**
+
+## 描述
+
+**<mark>TRACE</mark>** 是一款内置 4 组光电对管和 MEGA328 芯片的巡线模块。
+
+TRACE Unit 同样也是通过 IIC 与主控通信，其I2C地址是0x5A。与 M5Core 相连时，接在 GROVE A 口。
+
+<img src="assets/img/product_pics/unit/unit_trace_03.png" width="30%" height="30%">
+
+
+
+## 特性
+
+- 工作范围：反射面距离光电对管面小于 11mm
+-  GROVE接口，支持[UiFlow](http://flow.m5stack.com)编程，[Arduino](http://www.arduino.cc)编程
+
+## 相关链接
+
+- **[官方频道视频](https://i.youku.com/i/UNjE1ODA2MzE0OA==?spm=a2hzp.8253869.0.0)**
+
+- **[官方论坛](http://forum.m5stack.com/)**
+
+<!-- - **[模块内MEGA328固件](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Unit/Makey_NewVersion/firmware_328p)** -->
+
+## 例程
+
+### 1. Arduino IDE
+
+*以下仅为用法示意，并不完整。如果需要完整例程请点击[这里](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Unit/TRACE/Arduino)。*
+
+```arduino
+#include <M5Stack.h>
+#include "Wire.h"
+
+#define JOY_ADDR 0x52
+
+// declaration
+#define VALUE_SPLIT
+uint8_t value;
+int sensorValue[4] = {0};
+
+// initialization
+M5.begin();
+M5.Lcd.clear();
+dacWrite(25, 0);//disable the speak noise
+Wire.begin(21, 22, 400000);
+
+
+// read data
+Wire.requestFrom(JOY_ADDR, 3);
+if (Wire.available()) {
+  x_data = Wire.read();// X(range: 10~250)
+  y_data = Wire.read();// Y(range: 10~250)
+  button_data = Wire.read();// Z(0: released 1: pressed)
+  sprintf(data, "x:%d y:%d button:%d\n", x_data, y_data, button_data);
+}
+```
+
+### 2. UIFlow
+
+*具体例程请点击[这里](https://github.com/m5stack/M5-ProductExampleCodes/tree/master/Unit/TRACE/UIFlow)。*
+
+<img src="assets/img/product_pics/unit/unit_example/TRACE/example_unit_trace_01.png">
+
+<!-- ## 原理图
+
+<img src="assets/img/product_pics/unit/trace_sch.png"> -->
+
+### 管脚映射
+
+<table>
+ <tr><td>M5Core(GROVE接口A)</td><td>GPIO22</td><td>GPIO21</td><td>5V</td><td>GND</td></tr>
+ <tr><td>TRACE Unit</td><td>SCL</td><td>SDA</td><td>5V</td><td>GND</td></tr>
+</table>
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