本文介绍一种目前尚不为大家所熟知的八位微处理机。该微处理机是美国莫托罗拉公司继6800之后于1978年公布的一种高级八位CPU单片即6809,有人称它为软16位,或准16位,亦有称为8位和16位混合微处理机的。6809的性能比6800有了很大的改进和提高,它的处理能力比8080、6800高4～5倍,特别是指令系统功能已经达到了八位微处理机的高峰,性能方面超过了目前的八位微处理机,其影响在八十年代中期将明显呈现。下面我们从硬件、软件两方面分别阐述。 This article describes an eight-bit microprocessor that is not yet known to everyone. The microprocessor is the United States Motorola company following the 6800 in 1978 after the release of an advanced eight CPU chip or 6809, some people call it soft 16-bit, or quasi-16, also known as 8 and 16 Bit hybrid microprocessors. 6809 performance has been greatly improved than the 6800 and improve its processing power than 8080,6800 high 4 to 5 times, especially the command system features has reached the peak of eight microprocessors, the performance exceeds the current Eight microprocessors, the impact of which will be evident in the mid-eighties. Here we elaborate on hardware and software respectively.