。用8031单片机经8255A扩展2位8段码LED显示器，用8255A的A口作为段码（字形代码）数据口，PB0和PB1作为位控制端口。在位控制口加集电极开路的反相高压驱动器74LS06以提供驱动LED显示器所需的足够大的电流，然后接至各数码显示器的共阴极端。同理，在段码数据口集电极开路的正相高压驱动器74LS07提供足够大的电流，然后接到数码显示器的各段-Simple calculator needs 8 bit 2 segment code LED display circuit. With 8031 MCU by 8255A to extend the 8 bit 2 segment code LED display, with the A 8255A port as the segment code (font code) data port, PB0 and PB1 as a bit control port. In the position control port and an open collector of the reverse voltage driver 74LS06 to provide sufficient current to drive the LED display, and then connect to the common cathode of the digital display. Similarly, normal phase high voltage driver 74LS07 open circuit in the code segment data collector provide enough current, then each received digital display