fix documentation mistake

Author: William.Wu

sample/STM32/README.md

@@ -42,8 +42,8 @@ keil5系列软件中没有包含芯片器件库，需要自行安装否则会提
 将下载到的器件库导入到keil中即可。
 
 ##硬件接口
-  使用USART2作为Debug通道。端口为PB10，PB11分别对应stm32上USART2的TX、RX，连接串口等外部设备时将外部串口的TX端接到stm32的Rx上，波特率为115200，此处的波特率必须和串口调试助手的波特率一致；
-使用USART3作为和M100上的N1飞控通信的接口。端口为PA2、PA3分别对应USART3的TX、RX，和N1飞控的“USART_CAN2”端口连接。波特率为 921600.此处的波特率必须和N1飞控的波特率一致，可以在DJI调参软件中调整； 
+  使用USART2作为Debug通道。端口为PA2、PA3分别对应stm32上USART2的TX、RX，连接串口等外部设备时将外部串口的TX端接到stm32的Rx上，波特率为115200，此处的波特率必须和串口调试助手的波特率一致；
+使用USART3作为和M100上的N1飞控通信的接口。端口为PB10，PB11分别对应USART3的TX、RX，和N1飞控的“USART_CAN2”端口连接。波特率为 921600.此处的波特率必须和N1飞控的波特率一致，可以在DJI调参软件中调整； 
 ![硬件串口](image/硬件串口.png)
 ##开始使用
 >第一次使用前请连接手机和遥控器，并按照官网提示激活飞机。[更多关于激活](https://developer.dji.com/cn/onboard-sdk/documentation/ActivationGuide/)  
@@ -202,9 +202,9 @@ and then import this file from Keil's `Pack Installer`
 
 ##Hardware Installation
 
-Choose USART2 for debug. PB10, PB11 as stm32's TX, RX. When connect to an external device, link stm32-board's Rx to your device's TX. BaudRate is 115200.BaudRate here must be the same as BaudRate in your Serial debugging assistant.
+Choose USART2 for debug. PA2, PA3 as stm32's TX, RX. When connect to an external device, link stm32-board's Rx to your device's TX. BaudRate is 115200.BaudRate here must be the same as BaudRate in your Serial debugging assistant.
 
-Use USART3 for communicating with M100. PA2, PA3 as TX, RX, which should be plug in the "USART_CAN2" prot. The BaudRate here should equal to BaudRate of N1 flight control system on M100, which can be adjust on "DJI Assistant". 
+Use USART3 for communicating with M100. PB10, PB11 as TX, RX, which should be plug in the "USART_CAN2" prot. The BaudRate here should equal to BaudRate of N1 flight control system on M100, which can be adjust on "DJI Assistant". 
 ![硬件串口](image/硬件串口.png)
 
 ##Getting Start