基于EZ-USB FX2的数据采集系统USB接口设计

摘要

以CYPRESS公司的EZ⁃USB FX2芯片为基础，对工业CT数据采集系统的USB接口设计所涉及的几个方面进行了详细的介绍。该设计中为了能提高数据传输的速度，EZ⁃USB芯片采用Slave FIFO接口方式，在此方式下，USB内核不参与数据的传输。CY7C68013A芯片内部包含有4 KB的可配置端点缓冲区，这是大容量数据传输端点，可配置成不需要8051固件参与就同外围电路完成高速数据传输端。CYPRESS公司提供的EZ⁃USB固件程序开发包中包含有固件程序的基本框架。在此介绍CY7C68013A芯片的结构和特点，分析EZ⁃USB FX2固件程序框架，并给出固件程序实例代码，描述固件代码装载方式，应用程序调用驱动程序的接口函数。采用EZ⁃USB芯片开发USB接口，大大降低开发难度，提高开发效率。%Taking EZ⁃USB FX2 interface chip as an example,several aspects involved with USB interface design of indus⁃trial CT data acquisition system are introduced in detail in this paper. In this design,Slave FIFO is used in EZ⁃USB chip to im⁃prove the speed of data transmission. In this way, the USB kernel is not involved in the data transmission. Inside the CY7C68013A chip,4 kB configurable endpoint buffer is contained. It is the large capacity data transmission terminal,which can be configured to fulfill high⁃speed data transmission with peripheral circuit,but does not need 8051 firmware program to join with. The basic framework is contained in the EZ⁃USB firmware program development kit provided by CYPRESS company. In this paper,the structure and characteristics of the CY7C68013A chip are introduced,the EZ⁃USB FX2 firmware frame is ana⁃lyzed,the firmware example code is given,the firmware code loading way is described,and the interface between application program and driver is illustrated. With USB interface developed by means of EZ⁃USB chip,the development difficulty was great⁃ly reduced,and the development efficiency was improved.