Back to results
US 7,257,728 B2Granted
Method and apparatus for an integrated circuit having flexible-ratio frequency domain cross-overs
AssigneeIntel Corporation
InventorsJeffrey R. Wilcox, Gad S. Sheaffer
Life of this patent
Estimating the term…
Abstract
A method and apparatus for a integrated circuit having flexible-ratio frequency domain cross-overs. In one embodiment, an integrated circuit has at least three cooperating frequency domains with variable operating frequencies. The integrated circuit includes cross-over logic to allow integral fraction ratio frequency domain cross-overs between more than one pair of frequency domains.
Claims12
A clock domain cross-over apparatus comprising:
- a plurality of latches to latch data items;
- an array of status bits comprising one valid bit and one free bit for each of said plurality of latches;
- writer logic circuit to receive data into one of said plurality of latches and to toggle a writer indicator signal to cause a valid bit for that latch to be set;
- reader logic circuit to read data from one of said plurality of latches and to toggle a reader indicator signal to cause a free bit for that latch to be set;
- masking circuitry to delay toggling on said writer indicator signal and said reader indicator signal to maintain setup times above a predetermined threshold.
2 more elements
A mask generator comprising:
- a writer clock N value input to receive an N value indicative of a first number of ticks for a first frequency domain;
- a reader clock M value input to receive an M value indicative of a second number of ticks for a target frequency domain;
- a predetermined setup time indicator to indicate a minimum setup time, said minimum setup time being a minimum number of ticks;
- mask signal generation circuitry to compute and generate a mask signal from programmable values of N and M to mask signal transitions that occur within said minimum number of ticks in said target frequency domain of a transition of a clock signal in said target frequency domain.
1 more element
A method of transferring data from a first clock domain to a second clock domain, comprising:
- storing a data item in a first entry in an array;
- marking a free bit to indicate that said first entry is not free;
- signaling the data item is available by toggling to any state a writer indicator;
- continuing to receive data items in said array while free entries are available;
- receiving said data item in said second clock domain;
- signaling that the data item has been received by toggling to any state a reader indicator.
3 more elements
Dependencies are inferred from the claim text.