基于CPLD的开关和数码管驱动模块化设计

Modularization Design of Switch and Digital Tube Drive Module Based on CPLD

结合普通拨码开关和LED数码管的各自性能特点,分别介绍了实现8421码拨码开关和7段数码管译码的控制模块的设计方案,并给出主要的硬件选择及算法实现、软件仿真。研究此模块的目的,是通过应用Altera公司的EPM7192芯片实现单片机有限I/O口的扩展,解决普通可编程并行I/O接口芯片无法实现的功能复用且译码复杂等局限性。在此基础上将8421码拨码开关驱动与7段数码管驱动有机结合起来,一并解决两者硬件上无法融合的矛盾,节约了成本,增强了抗干扰性。该模块已经应用于真空溅射监控显示系统、新型真空计等开发项目中,在复杂的电磁场环境中依然能够稳定准确地运行。通过实践证明,该设计方案能同时驱动3位8421码拨码和2位7段数码管,并且还可以根据实际需要进行扩展。因此,具有较高的通用性、可靠性。

Combined with the performance characteristics of the common dial switch and LED digital tube,this paper introduces the design scheme of the decoding and control module of the seven-segment LED digital tube and 8421 dial switch,and gives the main hardware selection and algorithm realization,software simulation. The study of this module aims to achieve limited I / O port expansion using Altera company＇s chip-EPM7192,but also solve the limitations that the common programmable parallel I / O interface chip cannot realize the function reuse,and its decoding is complex. On the basis of this,the 8421 dial switch driver and the seven-segment LED digital tube driver are organically combined together to solve the contradiction that the hardware cannot be fused together The cost is saved,and the anti-interference ability is enhanced. The module has been applied in a vacuum sputtering monitoring display system,a new type of vacuum gauge and other development projects,it is still stable and can accurate operate in the complex electromagnetic field environment. It is proved by practice that the design scheme can drive 3 pieces of 8421 dial switch and 2 pieces of seven-segment LED digital tube at the same time,and can be extended according to the actual needs. So the drive module has high universality and reliability.