External Memory Interface Handbook Volume 3: Reference Material: For UniPHY-based Device Families

ID 683841
Date 3/06/2023
Document Table of Contents

7.1.3. Command Issuing FSM

The command issuing finite-state machine (FSM) has three states.

The controller is in the INIT state when the PHY initializes the memory. Upon receiving the afi_cal_success signal, the state transitions to INIT_COMPLETE. If the calibration fails, afi_cal_fail is asserted and the state transitions to INIT_FAIL. The PHY receives commands only in the INIT_COMPLETE state.

When a refresh request arrives at the state machine at the same time as a read or write request, the refresh request takes precedence. The read or write request waits until there are no more refresh requests, and is issued immediately if timing requirements are met.