TMS320C54x的McBSP串口与PS/2键盘接口通信设计

TI公司的TMS320C54x系列的DSP不具有方便的人机接口。实现与PS／2键盘的直接通信，无论是调试系统还是应用于实际的工程都具有一定的意义。在详细分析McBSP串口的各种工作方式和PS／2键盘协议的基础上，发现PS／2键盘与主机的数据交换采用了类似于同步串口的通信协议，只是没有帧同步信号。研究PS／2协议发现，McBSP串口接收数据时，PS／2接口的DATA数据线的起始位可以作为McBSP串口接收的帧同步信号；McBSP串口发送数据时，PS／2接口的CLOCK时钟线可以作为McBSP串口发送的帧同步信号。从而利用了最少的硬件资源实现了同PS／2键盘的连接。在软件上利用了McBSP串口的灵活配置并采用了中断的方式节约了CPU的软件开销。实践证明设计的通信方法是切实可行的。

Communication Design between TMS320C54x McBSP and PS/2 Keyboard

TMS320C54x DSP family does not provide flexible interface between human and machine The direct communication between DSP and PS/2 keyboard is significant for debugging DSP system or applying engineering The modes of McBSP serial port and the protocol of PS/2 keyboard are analyzed in detail The communication protocol between PS/2 keyboard and host is similar to synchronous serial port except that it does not have frame signal In the way of applying the start bit on DATA as receiver frame signal and the start signal on CLOCK as transmitter frame signal, the feasibility of communication between McBSP and PS/2 is achieved As a result, few hardware resources are used in the interface between McBSP and PS//2 keyboard to design the communication In the aspect of software, the flexible configuration of McBSP and interrupt means are adopted to cut down the CPU timeconsuming The actual results show that the communication design is simple, reliable and practical