Data transfer between clock domains

A system for transferring a data signal from a first clock domain to a second clock domain, wherein the first clock domain comprises a first clock and the second clock domain comprises a second clock, the system comprising:

• a signal input for receiving an input signal from the first clock domain;
• a checking circuit portion for checking whether the slower of the first or second clock is in a part of its cycle away from a forthcoming transition, said checking circuit portion being clocked by the faster of the first or second clock;
• and
• a transferring circuit portion for transferring the input signal to the second clock domain if the checking means determines that the slower clock is in part of its cycle away from a forthcoming transition.

A method of transferring a data signal from a first clock domain to a second clock domain, wherein the first clock domain comprises a first clock having a frequency greater than a frequency of a second clock in the second clock domain, the method comprising:

• receiving an input signal from the first clock domain;
• checking whether the second clock domain is in a part of its cycle away from a forthcoming transition using checking means clocked by the first clock;
• and
• transferring the input signal to the second clock domain if the check determines that second clock is in a part of its cycle away from a forthcoming transition.

A method of transferring a data signal from a first clock domain to a second clock domain, wherein the first clock domain comprises a first clock and the second clock domain comprises a second clock, the method comprising:

• receiving an input signal from the first clock domain;
• checking whether the slower of the first or second clock is in a part of its cycle away from a forthcoming transition using checking means clocked by the faster of the first or second clock;
• and
• transferring the input signal to the second clock domain if the check determines that slower clock is in a part of its cycle away from a forthcoming transition.