| 摘要 |
A special test mode is incorporated within a USB transceiver of a digital system, and when the special test mode is activated, USB eye pattern test data signal waveforms, e.g., a continuous stream of USB state transitions (defined by the USB specification) are transmitted on the USB data lines connected to the USB transceiver. Conventional test equipment may be attached to the USB data lines and the signal quality monitored. Circuit changes can be made to the digital system and the results easily measured. When the USB eye pattern test data signal waveforms on the USB data lines of the digital system are of satisfactory quality, the special test mode may be turned off and the USB transceiver will resume operation as a normal USB device.
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