Serial peripheral interface

摘要

For an integrated circuit (IC) that retrieves data from a memory device external to the IC, a novel memory interface module that generates a sampling clock to the memory device and samples the retrieved data is described. The memory interface module adjusts the frequency of the sampling clock and selects a sampling time for sampling the retrieved data. The memory interface includes a training module that monitors a data pin of the memory device for transitions. The training module searches and records the earliest transition and the latest transition with respect to the period of the sampling clock. The memory interface module uses the earliest transition and the latest transition to determine an interval of data uncertainty (uncertainty interval) for the data pin. The memory interface module facilitates determining a new sampling time and a new sampling clock frequency based on the uncertainty intervals.