Abstract: Various clock frequency dividers are disclosed. Each frequency divider includes cascaded flip-flops and a feedback logic gate. First data inputs of the flip-flops are for propagating logic values along the cascaded flip-flops and the feedback gate for generating valid states of a sequence in response to a clock signal. Each frequency divider includes an invalid state elimination circuit configured to detect an invalid state at the outputs of the flip-flops and change it into a valid state in response to the clock signal. In some implementations, the invalid state elimination circuit includes a NOR gate to detect an all-zero invalid state and generate a control signal to cause the flip-flops to output logic values associated with a valid state or to cause a multiplexer to introduce a logic value associated with a valid state. In other implementations, the invalid state elimination circuit instead includes an AND gate to detect an all-ones invalid state.

Abstract: Various clock frequency dividers are disclosed. Each frequency divider includes cascaded flip-flops and a feedback logic gate. First data inputs of the flip-flops are for propagating logic values along the cascaded flip-flops and the feedback gate for generating valid states of a sequence in response to a clock signal. Each frequency divider includes an invalid state elimination circuit configured to detect an invalid state at the outputs of the flip-flops and change it into a valid state in response to the clock signal. In some implementations, the invalid state elimination circuit includes a NOR gate to detect an all-zero invalid state and generate a control signal to cause the flip-flops to output logic values associated with a valid state or to cause a multiplexer to introduce a logic value associated with a valid state. In other implementations, the invalid state elimination circuit instead includes an AND gate to detect an all-ones invalid state.

Abstract: Systems and methods to provide a low-power mode for serial links are disclosed. One embodiment of such a system includes a transmitter coupled to a link; a receiver coupled to the link and configured to receive signals over the link from the transmitter; a transmit control module configured to cause the transmitter to enter and exit a low-power mode; and a clock module coupled to the transmitter and configured to provide a clock signal to the transmitter, wherein the clock module is further configured to provide the clock signal as a divided clock signal to the transmitter when the transmitter is in the low-power mode, further wherein the divided clock signal has a same phase as the clock signal before entry into the low-power mode.

Abstract: Systems and methods to provide a low-power mode for serial links are disclosed. One embodiment of such a system includes a transmitter coupled to a link; a receiver coupled to the link and configured to receive signals over the link from the transmitter; a transmit control module configured to cause the transmitter to enter and exit a low-power mode; and a clock module coupled to the transmitter and configured to provide a clock signal to the transmitter, wherein the clock module is further configured to provide the clock signal as a divided clock signal to the transmitter when the transmitter is in the low-power mode, further wherein the divided clock signal has a same phase as the clock signal before entry into the low-power mode.