便携式测量仪大容量RAM及USB接口的设计

Design of Mass RAM and USB Interface in Portable Measurement Instrument

以CH372A(USB接口)和LH5P8512(伪静态RAM)芯片为例,介绍基于AT89C51微处理器的便携式测量仪大容量RAM及USB接口的设计方案。对RAM存储器和USB接口电路的组成和管理做了详细说明,并对CH372A的命令字和通信模式做了介绍,针对数据上传和下传通信程序以及API函数做了系统地论述。实践证明,该设计方案硬件成本低、软件编写简便,有通用性。

The design project of mass RAM and USB interface in portable measurement instrument is introduced based on AT89C51 microprocessor. CH372A （USB Port）and LHSP8512（Pseudo Static RAM） chip are the examples. Not only it introduces the composition and management of RAM memory and USB interface circuit in detail, but also mentions the command words and communication mode of the CH372A. The communication programe in up -data and down -data are also expounded. API function is explained in system as well. The practice proves that this design project reduces the cost of hardware, simplicies the software compilation and is full of common use.