Patent ID: 8099633

Claim:
A USB (Universal Serial Bus) test circuit incorporated in a USB device for actualizing a USB connection and used for a compliance test of the USB device, said circuit comprising: an input portion that receives from an external device a test signal including operation mode information of said circuit and a timing signal synchronized with each bit data of the operation mode information; and a generation portion that generates a packet to be measured for testing signal quality and outputs the packet, said input portion receiving the operation mode information including a packet type of the packet to be measured which is desired to be generated, an endless flag that indicates whether or not to repeatedly generate and output the packet to be measured and a number of transmission bytes per packet of the packet to be measured which is desired to be generated, and extracting each bit data of the operation mode information at a timing corresponding to the timing signal and synchronized with a clock signal in the USB device, said generation portion generating the packet to be measured depending on the operation mode information inputted to said input portion.