使用avr单片机完成一个简单系统，有2 个按键和8 个LED 数码管作为显示。两个按键分别代表输入字符“a”和“b”，且具备类似PC 机键盘的连发功能：如按下“a”键不放，第1 秒内输入1 个“a”，以后每隔0.2 秒输入一个“a”……。输入的“a”在8 个LED 数码管上由右向左移动。-Avr microcontroller using a simple system complete with two keys and 8 LED digital tube as the display. Enter the two keys representing the characters " a"　and " b" , and the PC-keyboard with similar bursts of features: such as pressing the " a"　key, the first 1 second, enter an " a" , after every 0.2 seconds to enter a " a"　... .... Enter the " a"　in the 8 LED digital tube moving from right to left.