利用AT89S51单片机来制作一个手动计数器，在AT89S51单片机的P3.7管脚接一个轻触开关，作为手动计数的按钮，用单片机的P2.0－P2.7接一个共阴数码管，作为00－99计数的个位数显示，用单片机的P0.0－P0.7接一个共阴数码管，作为00－99计数的十位数显示-AT89S51 microcontroller used to create a manual counter, in the AT89S51 MCU P3.7 pin by one touch switch, a manual count of the button with a microcontroller P2.0-P2.7 by one common cathode LED, as a 00- 99-digit display count, with P0.0-P0.7 microcontroller then a common cathode LED, as a 00-99 count in the ten-digit display