USB communication system, USB devices, and anomaly detection method of USB communication system

摘要

PPROBLEM TO BE SOLVED: To provide an USB communication system, a USB device, and a method for detecting abnormality in the USB communication system capable of abnormal detection wherever a physical interruption of the USB communication occurs and detecting abnormality due to logical communication disconnection as well. PSOLUTION: In the USB communication system composed by connecting an upper device 2 and a card reader 1 with a USB cable 3, the card reader 1 has: a bus reset execution means for executing bus rest as pre-processing in setting the higher-level device 2 and a logical communication line; a time measurement means for measuring a time when a one's self is in a bus reset state; and an interruption processing execution means for executing communication interruption processing automonously. PCOPYRIGHT: (C)2008,JPO&INPIT