7279 键盘及led的显示利用HD7279A 控制键盘和显示，要求任意按下键，在LED 最右 位显示对应键号值，其余显示值左移一位。-Show utilize HD7279A 7279 and led the keyboard control keyboard and display, requiring any key is pressed, the LED rightmost Displays the corresponding key number, and the remain