u盤驅(qū)動程序 通用串行總線(USB Universal Serial Bus)是一種計算機與外部設(shè)備連接的新技術(shù)，相對于PC傳統(tǒng)的串/并行接口，USB具有較高的數(shù)據(jù)傳輸率、即插即用、熱插拔、易擴充和低成本等優(yōu)點。從USB標準頒布以來的短時間內(nèi)，USB已成為PC必備的標準接口。
51串行令牌格式 a51編譯
Read data from serial port
and write into buffer DPTR pointed in XRAM if a data frame is
received and calculate the check sum
if a information frame is received return control byte only
