位填充导致USB数据传输紊乱的一种解决方案

通用串行总线(USB)数据传输中要对数据进行非归零翻转(NRZI)编解码、添加/去除位填充和串并/并串转换。添加/去除位填充使每字节数据传输所需的时间发生变化,再加上收发器与协议层的时钟频率不同,从而可能导致数据紊乱。以USB 2.0设备控制器中的收发器为例,在收发器与协议层间添加异步先入先出存储器(FIFO)作为缓存区可以解决这一问题。EDA软件仿真验证了该方法的可行性。

A solution for USB 2.0 data transfer disorder caused by bit stuffing

The Universal Serial Bus(USB) transfer data should adopt None Return Zero Invert(NRZI) encoding and decoding,add/remove bit stuffing,and series to parallel/parallel to serial conversion.Add/remove bit stuffing changes the data transfer time per-byte,coupled with the different clock frequency of transceiver and protocol layer,may lead to data distortion.Take transceiver in the USB 2.0 device controller as an example,this paper proposed a method to solve this problem by using asynchronous first in first out memory(FIFO) as buffer between transceiver and protocol layer.The results of EDA simulation show that the proposed method can solve the data distortion perfectly.