自动伸缩门电路原理
Circuit principle of automatic expansion door
电路的核心是80C51单片机，其内部带有4KB的FlashROM,无须扩展程序存储器;电脑没有大量的运算和暂存数据，现有的128B片内RAM已能化粪池模具 路缘石模具 唐山通风管道 塑钢电缆挂钩 钢纤维 钢制拍门 植绒机 铜雕佛像满足要求，也不必扩展片外RAM，系统配备4位LED显示和2个单接口键盘，采用P0接口外接8路反相三态缓冲器74LS244作LED动态扫描的段码控制驱动信号,用P1接口的P1.0-P1.3外接一片集电极开路反相门电路74LS07做为4位LED的位选信号驱动口， LED共阴极端与74LS07的输出端相连;按键接口，由P2.0,P2.1来同时完成数字信号的接收。P3口接D/A转换器，将单片机处理后的信号转换成模拟信号通过电动机将电能变成机械能驱动自动伸缩门完成开关。
The core of the circuit is 80C51 single chip microcomputer, which is equipped with 4KB flash ROM inside, so there is no need to expand program memory; the computer does not have a large amount of calculation and temporary storage data, and the existing 128B on-chip RAM can meet the requirements, and there is no need to expand the off-chip ram. The system is equipped with 4-bit LED display and 2 single interface keyboards, and the P0 interface is connected with 8-way inverted tristate buffer 74ls244 as the segment code control driver of LED dynamic scanning. For signal, use p1.0-p1.3 of P1 interface to connect a collector open inverse gate circuit 74ls07 as the bit selection signal driving port of 4-bit led, and the LED common negative terminal is connected with the output terminal of 74ls07; for key interface, p2.0 and p2.1 are used to receive the digital signal at the same time. P3 port is connected with a D / a converter, which converts the signal processed by the single-chip microcomputer into an analog signal. Through the motor, the electric energy is transformed into mechanical energy to drive the automatic expansion door to complete the switch