USB3.0物理层中弹性缓冲的设计与实现

Design and Implementation of Elastic Buffer for USB3.0 PHY

弹性缓冲用于在不同的时钟域中同步数据以保持数据的完整性,在USB、PCIE等高速串行总线的物理层中普遍应用.通过分析弹性缓冲的作用机制,根据USB3.O的协议要求,采用具有写指针屏蔽、指针跳跃、断点保存与握手、输出控制等具有创新功能的异步FIFO来设计弹性缓冲,很好实现了时钟频率补偿的目的.所设计的弹性缓冲采用并行10位数据,读写时钟可达到500 MHz的频率.该研究结论可用于满足USB3.0协议的弹性缓冲等高速弹性缓冲的场合,具有一定的工程应用价值.

Elastic Buffers which are applied in USB3.0 and PCIE physical layer are used to ensure data integrity when bridging two different clock domains. By the research of elastic buffer mechanism and USB3.0 specification, an elastic buffer is designed by using asynchronous FIFO which has innovative function including write pointer mask, breakpoint restored, pointer jump, handshake methods and output control, and the frequency delta is managed perfectly by this elastic buffer. The width of input and output data is 10 bits, and the write clock and read clock can achieve 500 MHz. The research result can be applied to elastic buffer of USB3.0 and other system where high speect elastic buffer is needed, and is valuable to enuineering application to some extent.