USB interface and testing method thereof

A testing method for a USB interface, comprising the following steps:

• providing a test signal to a USB transceiver macrocell;
• sampling the test signal and outputting the test signal after a predetermined time;
• converting the test signal to USB protocol, outputting a first converted signal through a transmitter, receiving the first converted signal through a receiver, and converting the received first converted signal to a second converted signal;
• and
• comparing the second converted signal with the test signal and then outputting an error-acknowledging signal.

A testing method for a USB transceiver macrocell, comprising the following steps:

• providing a test signal to the USB transceiver macrocell;
• sampling the test signal and outputting the test signal after a predetermined time;
• converting the test signal with a USB protocol and outputting a converted signal by the USB transceiver macrocell;
• and
• comparing the converted signal with the test signal and then outputting an error-acknowledging signal.

A USB interface, comprising:

• a test signal generator for generating a test signal;
• delay logic for delaying the test signal;
• a USB converter logic coupled to the test signal generator,
• the USB converter logic including logic for converting the test signal into a USB protocol signal,
• circuitry for receiving the USB protocol signal and looping the signal back to the USB converter logic;
• logic within the USB converter circuit for converting the loop-backed signal into a loop-backed converted signal having a protocol comparable to the test signal;
• and
• a comparator coupled to the USB converter circuit, the comparator configured to compare the loop-backed converted signal with the delayed test signal.

A testing method for a USB transceiver, comprising:

• providing a test signal to a USB signal converter;
• sampling the test signal and outputting the test signal after a predetermined time;
• converting the test signal with a USB protocol and outputting a converted signal by the USB signal converter;
• and
• comparing the converted signal with the test signal and then outputting an error-acknowledging signal.