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本文介绍一个价廉物美的袖珍PC。它通过一块NE556同时控制程序计数器的CP、SRAM的WE和I/O,可方便地向SRAM各单元写入“0”或“1”,从而对各种执行机构实现开、闭环控制。本袖珍PC的主体是一块NE 556和一块2114SRAM。NE556构成2114的“0”、“1”写入电路,2114则完成时间序列(0、1)的存贮和输出,具有1024个控制点。为了扩展应用,系统中设置了一路定时器,定时器的输出与2114的读出信号相“与”后经光耦/可控硅电路作用于执行机构。系统方框图如图1所示。图2所示为原理电路图。 1.整形及分频。为了降低系统对时钟脉冲的要求,设置了该单元。分频电路将固定时钟频率分
This article describes a cheap pocket PC. Through a NE556 which controls the program counter’s CP, SRAM’s WE and I / O at the same time, it can easily write “0” or “1” to each SRAM cell to realize open and closed loop control for various actuators. The main body of this pocket PC is a NE 556 and a 2114SRAM. The NE556 writes “0” and “1” write circuits to 2114, while 2114 completes the storage and output of the time series (0,1) with 1024 control points. In order to expand the application, a timer is set in the system. The output of the timer and the readout signal of the 2114 are ANDed to the actuator through the optocoupler / thyristor circuit. System block diagram shown in Figure 1. Figure 2 shows the schematic circuit. 1. Plastic and frequency. In order to reduce the system clock pulse requirements, set up the unit. The frequency division circuit divides the fixed clock frequency