Frequency adjusting method of a CDR circuit and apparatus thereof

A receiver apparatus, for receiving an outer data signal of an outer apparatus, comprising:

• a phase-lock loop (PLL), for outputting a transmitter clock according to an operational frequency of the receiver apparatus;
• a CDR circuit, for receiving the outer data signal and outputting a receiver clock, wherein the receiver clock follows the outer data signal when the CDR circuit is set in a phase mode and follows the transmitter clock when the CDR circuit is set in a frequency mode;
• a frequency detector, for detecting the difference between the frequencies of the receiver clock and the transmitter clock and outputting a dispersion detective signal according to the difference;
• and
• a reset controller, for sending out a reset signal to the CDR circuit to restart the CDR circuit when the frequency detector outputs the dispersion detective signal;
• wherein when the CDR circuit is set in the phase mode, and the frequency detector outputs the dispersion detective signal, the CDR circuit is restarted and switched to the frequency mode, otherwise, the CDR circuit remains in the phase mode.

A frequency adjusting method of a receiver apparatus including a clock/data recovery (CDR) circuit that generates a receiver clock, the receiver apparatus operating in a first operational frequency, the receiver apparatus connected to an outer apparatus and adjusting the receiver clock for receiving an outer data signal, the outer apparatus operating in a second operational frequency, the frequency adjusting method comprising:

• (a) setting the receiver clock to follow the second operational frequency;
• (b) detecting whether the receiver clock has a frequency beyond a normal operational value when the receiver clock follows the second operational frequency;
• (c) when the receiver clock is beyond the normal operational value, restarting the CDR circuit of the receiver apparatus and setting the receiver clock to operate at the first operational frequency;
• and
• (d) setting the outer apparatus to operate in the first operational frequency when the outer apparatus does not receive a response from the receiver apparatus within a predetermined time,
• wherein the receiver clock follows the first operational frequency when the receiver apparatus is not connected to the outer apparatus.