以單晶微電腦製作之多通道波寬調變信號產生器

A Multiple Channel PWM Signal Generator Made of a Single-chip Microcomputer

劉漢平(Han-Ping Liu)

《中華技術學院學報》 34期 (2006/06) Pp. 185-196

https://doi.org/10.7095/JCIT.200606.0185

摘要

PWM （Pulse Width Modulation，波寬調變）信號產生器在現有單晶微電腦內是常見的週邊，其製作方式都是採用硬體而且數量有限。若是我們嚐試以一個單晶微電腦產生多組PWM信號，勢必要使用程式來達成。使用程式產生單一PWM信號雖然十分簡單，但是其效能受限於傳統程式的串列執行特性，所以很難同時產生頻率較高、工作週期解析度較高且數量較多的PWM信號。
在此文章中的設計方式，使用平行化概念撰寫程式，並適當地搭配單晶微電腦上的資源，可以高度發揮一般單晶微電腦效能。以標準版的8051 搭配11.0592MHz的時脈，可以產生多達8組1KHz，工作週期解析度1%且各自獨立的PWM信號。
在理論分析上，可以使用平行化的概念來分析設計方式。同時，在古中國兵法中“以空間換取時間”的概念也導入作為設計技巧的解釋。

關鍵字

波寬調變 ； 平行化 ； 單晶微電腦

並列摘要

PWM (Pulse Width Modulation) signal generator is a popular peripheral which is always hardware type and few built in the single-chip microcomputer. We have to use only software in a single-chip microcomputer to generate more PWM signals if we need a lot. Although the single PWM signal is very easy to be generated by software, it is hard to generate independent multiple PWM signals of high frequency and high resolution. Due to the serial executed program, the performance of the single-chip microcomputer is not high enough to satisfy the above requirements.
In this article, we try to improve the performance for the above challenge even with a general purpose single-chip microcomputer. By applying the concept of parallelism to the output port and using redundant memory in the single-chip computer, we extremely improve the total equivalent performance for updating the multiple independent output bit. Using a standard version 8051 with 11.0592MHz clock, 8 independent PWM signals are generated with specification of 1 KHz frequency and 1% resolution.
The design may be clearly analyzed with concept of parallel computing. By the way, we introduce the rule from ancient Chinese tactics, ”replaced the spatial resource with the dominant of temporality”, as the explanation of practical skills.

並列關鍵字

PWM Pulse Width Modulation ； parallelism ； single-chip microcomputer