Patent ID: 8135872

Claim:
A USB controller, comprising: a link layer; and a physical layer configured to receive data from the link layer; and wherein said physical layer includes: a sequence control unit configured to output a transmitting enable signal and a receiving enable signal, and configured to control a sequence of transmission and reception of data based on the transmitting enable signal and the receiving enable signal; an analog front end configured to perform an analog-to-digital conversion process for data transmitted to the analog front end from the sequence control unit; and a test sequence control unit configured to transmit a loop-back enable signal to the analog front end; wherein the analog front end includes: a drive unit configured to transmit transmission data; a receiver unit configured to receive reception data; and a switch unit; wherein, when a test mode is selected as an operation mode, the physical layer transmits test data to the drive unit; the drive unit transmits the test data to the receiver unit; and the receiver unit transmits the test data to the sequence control unit; and wherein the switch unit transmits the transmitting enable signal to the receiver unit, and causes the receiver unit to transmit the test data to the sequence control unit, based on the loop-back enable signal from the test sequence control unit.