说明：  avr单片机，通过编辑键盘实现定义按键，按键连续按可以连续发送字符，并且在数码管上显示出来，在vc中可以编辑，也可以在cvavr下编辑运行
(avr microcontroller achieved by editing the definition of the keyboard keys, key continuous press can send characters continuously, and displayed on the digital control in vc can edit, you can edit to run under the cvavr)