A method for application in a data interface controller receiving asynchronous
input data at predetermined one of a plurality of input bit frequencies, wherein
the input data is sampled by the interface controller at a sample rate greater
than the predetermined input bit rate, and wherein the sample rate is variable,
and wherein the interface controller provides output data corresponding to the
input data, but delayed by a delay amount that varies in accordance with the sample
rate. The method is for providing a responsive signal event, responsive to a reference
event in the delayed input data and at a predetermined time relative to an input
bit time. In the method, a reference timing number is stored, representing the
predetermined time in periods of the predetermined input bit frequency. An adjustment
number corresponding to the delay amount is determined, in periods of the predetermined
input bit frequency. The adjustment number is subtracted from the reference timing
value to determine an adjusted timing number. A reference event is detected in
the delayed input data, and in response thereto an adjusted timing number of periods
of the predetermined input bit frequency is counted. A responsive signal event
is provided at the time when the counting has ended.
