Clock signal generating apparatus capable of reducing or avoiding crosstalk and glitch signals, and method used in clock signal generating apparatus

摘要

A clock signal generating apparatus includes a first frequency generating circuit, a second frequency generating circuit, and an output circuit. The first frequency generating circuit is arranged to generate a first clock signal having a first oscillation frequency. The second frequency generating circuit is arranged to generate a second clock signal having a second oscillation frequency. The output circuit is arranged to receive the first and second clock signals. The output circuit is able to output one of the first and second clock signals as an output clock signal according to an oscillation frequency control setting provided by an external bounding pad included within the clock signal generating apparatus.

主权项

1. A clock signal generating apparatus, comprising:
a first frequency generating circuit for generating a first clock signal having a first oscillation frequency; a second frequency generating circuit for generating a second clock signal having a second oscillation frequency; an output circuit, coupled to the first frequency generating circuit and the second frequency generating circuit, for receiving the first clock signal and the second clock signal, the output circuit including a first output terminal and a second output terminal, the output circuit being arranged to output one of the first and second clock signals as an output signal outputted via the first output terminal and to output the other of the first and second clock signals as an output signal outputted via the second output terminal according to a same oscillation frequency control setting; and a setting signal selection circuit, coupled to the second frequency generating circuit, for selecting one of a first setting signal and a second setting signal according to the oscillation frequency control setting, and outputting a selected setting signal to the second frequency generating circuit for adjusting the second frequency generating circuit.