Add doc about the new motion service.

Author: JF002

doc/MotionService.md

@@ -0,0 +1,17 @@
+# Motion Service
+## Introduction
+The motion service exposes step count and raw X/Y/Z motion value as READ and NOTIFY characteristics.
+
+## Service
+The service UUID is **00020000-78fc-48fe-8e23-433b3a1942d0**
+
+## Characteristics
+### Step count (UUID 00020001-78fc-48fe-8e23-433b3a1942d0)
+The current number of steps represented as a single `uint32_t` (4 bytes) value.
+
+### Raw motion values (UUID 00020002-78fc-48fe-8e23-433b3a1942d0)
+The current raw motion values. This is a 3 `int16_t` array:
+
+ - [0] : X
+ - [1] : Y
+ - [2] : Z

doc/ble.md

@@ -29,14 +29,15 @@ When the service does not exist in the BLE specification, InfiniTime implement c
 The following custom services are implemented in InfiniTime:
 
  - Since InfiniTime 0.8:
-   ```
-    * Music Service :             00000000-78fc-48fe-8e23-433b3a1942d0
-   ```
-   
+    * Music Service : 00000000-78fc-48fe-8e23-433b3a1942d0
+ 
+
  - Since InfiniTime 0.11:
-   ```
-     * Navigation Service :        00010000-78fc-48fe-8e23-433b3a1942d0
-   ```
+     * [Navigation Service](NavigationService.md) : 00010000-78fc-48fe-8e23-433b3a1942d0
+ 
+  
+ - Since InfiniTime 1.7:
+   * [Motion Service](MotionService.md) :        00020000-78fc-48fe-8e23-433b3a1942d0
 
 ## BLE services
 [List of standard BLE services](https://www.bluetooth.com/specifications/gatt/services/)