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Please press enter key when you see the main menu on the screen.

屏幕上出现主菜单时请按键。

For text-mode files, carriage return–linefeed pairs are counted as single characters.

对文本模式的文件，作为一个字。

Serial.print(b, BYTE) prints b as a single byte followed by a carriage return and a linefeed.

以单个字节出b，并同时跟随一个和。