Strobe signal management to clock data into a system
AssigneeXilinx, Inc.
InventorsRichard W. Swanson, Tao Pi
Life of this patent
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Abstract
A method of communicating with a source synchronous device can include determining an expected number of pulses of a strobe signal to be received in response to a first read request directed to the source synchronous device and receiving the strobe signal from the source synchronous device. Pulses in the strobe signal can be counted. Responsive to detecting a last pulse of the expected number of pulses of the strobe signal, the strobe signal can be replaced with a reference signal that is phase and frequency aligned with the strobe signal.
Claims20
A method of communicating with a source synchronous device, the method comprising:
- determining an expected number of pulses of a strobe signal to be received in response to a first read request directed to the source synchronous device;
- receiving the strobe signal from the source synchronous device;
- counting pulses in the strobe signal;
- and
- responsive to detecting a last pulse of the expected number of pulses of the strobe signal, replacing the strobe signal with a reference signal that is phase and frequency aligned with the strobe signal.
A system for communicating with a source synchronous device, the system comprising:
- a pulse controller configured to count pulses from the source synchronous device received in a strobe signal responsive to a first read request, wherein the pulse controller is configured to detect a last pulse of a predetermined number of expected pulses;
- and
- a multiplexer coupled to the pulse controller and configured to selectively pass a strobe signal or a reference signal responsive to an instruction received from the pulse controller, wherein the reference signal is phase and frequency aligned with the strobe signal;
- wherein responsive to the pulse controller detecting the last pulse, the pulse controller is configured to instruct the multiplexer to pass the reference signal in lieu of the strobe signal.
A system for communicating with a source synchronous device, the system comprising:
- a delay line configured to apply an adjustable amount of delay to a reference signal;
- at least one frequency divider coupled to the delay line and configured to generate a first frequency divided signal and a second frequency divided signal from a version of the reference signal output from the delay line, wherein the first and the second frequency divided signals have a same frequency and a different phase;
- a phase detector configured to determine a phase relationship between a strobe signal and at least one of the first frequency divided signal or the second frequency divided signal;
- and
- an output selector coupled to the at least one frequency divider, wherein the output selector is configured to pass the first frequency divided signal or the at least a second frequency divided signal according to a counter that indicates adjustments in the amount of delay applied by the delay line,
- wherein the delay line adjusts an amount of delay applied to the reference signal responsive to the phase relationship determined by the phase detector, and
- wherein responsive to the delay line rolling over, the amount of delay applied to the reference signal is adjusted and the second frequency divided signal is output.
Dependencies are inferred from the claim text.