Description
There are no guidelines from Altera® about when to reset the DPA when using Soft-CDR in Stratix® III and Stratix IV devices. The rx_reset resets the DPA circuitry and the FIFO contents. However, rx_reset may be asserted when link retraining is needed for the DPA to lock to a new phase.
In Soft-CDR mode, the rx_reset does not need to be asserted as the DPA continuously locks to a new phase depending on ppm differences between the reference clock and the incoming data.