PA4-----控制摄像头模块开关 PA3-----单片机接收摄像头模块引脚（RX） WiFi摄像头波特率19200 PB1-----TIM3_CH4输出PWM PB9-----TIM4_CH4输出PWM(PA4----- control camera module switch PA3----- MCU receives the camera module pin (RX). WiFi camera baud rate 19200 PB1-----TIM3_CH4 outp