A method and apparatus for a calibrated variable phase offset timing
between synchronous clock subdomains is described. In one embodiment, the
invention is an apparatus. The apparatus includes a first subsystem and a
second subsystem coupled to the first subsystem. The apparatus also
includes a clock signal generator coupled to the first subsystem and
coupled to the second subsystem. The clock signal generator is to supply
a first clock to the first subsystem and to supply a second clock to the
first subsystem and to supply a third clock to the second subsystem. Each
of the first clock, the second clock and the third clock are derived from
a common clock, the first clock having a first predetermined phase offset
relative to the third clock, and the second clock having a second
predetermined phase offset relative to the third clock. The first
predetermined phase offset and the second predetermined phase offset are
adjustable based on performance characteristics of the first subsystem
and performance characteristics of the second subsystem.