使用串口0作为调试接口

1 ## Support Commands 2 ### Audio Commands 3 - play n: Play music with given index 4 - play URI: Play music by given URI, e.g.'play file://sdcard/test.mp3'. 5 - pause: Pause the playing music 6 - resume: Resume the paused music 7 - stop: Stop the playing music. 8 - setvol: Set volume 9 - getvol: Get volume10 - getpos: Get current position in seconds.11 12 ### System Commands13 - reboot: Restart system14 - free: Get the free memory15 - stat: Show the processor time amongst FreeRTOS tasks16 - tasks: Get information about running tasks17 - join: Connect Wi-Fi with ssid and password18 - wifi: Get connected AP SSID