188.8.131.52. Rate Match FIFO
The rate match FIFO compensates for the frequency differences between the local clock and the recovered clock up to ± 300 ppm by inserting and deleting skip/idle characters in the data stream. The rate match FIFO has several different protocol specific modes of operation. All of the protocol specific modes depend upon the following parameters:
- Rate match deletion—occurs when the distance between the write and read pointers exceeds a certain value due to write clock having a higher frequency than the read clock.
- Rate match insertion—occurs when the distance between the write and the read pointers becomes less than a certain value due to the read clock having a higher frequency than the write clock.
- Rate match full—occurs when the write pointer wraps around and catches up to the slower-advancing read pointer.
- Rate match empty—occurs when the read pointer catches up to the slower-advancing write pointer.
Rate match FIFO operates in six modes:
- Basic single width
- Basic double width
- PIPE 0 ppm