使用TF卡更新固件：
	  保存 bin 文件至 TF 卡根目录 , 并删除 TF 卡中的其它文件。断电状态下将 TF 卡插入机器，
	  机器通电自动更新。更新过程蜂鸣器会一直发出响声，响声结束则更新完成（期间不可断电）。
Firmware-Upgrade with TF card:
      Save the “.bin” file in the root directory of the TF card, and delete other files in TF card. Insert the TF card into the machine when powered off , and it will updade automatically when powered on. 
	  The buzzer will sound in the update process. When the update is completed, the sound will stop (do not power off in the update process)