External Memory Interfaces (EMIF) IP User Guide: Agilex™ 5 FPGAs and SoCs

ID 817467
Date 4/01/2024
Public

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5.1.1. Calibration

Calibration occurs shortly after the memory device is initialized, to compensate for uncertainties in the hardware system, including silicon PVT variation, circuit board trace delays, and skewed arrival times. The Agilex™ 5 FPGA EMIF IP provides skip calibration mode for simulating the design example.

Skip Calibration Mode

In Skip Calibration mode, the calibration processor assumes an ideal hardware environment, where PVT variations, board delays, and trace skews are all zero. Instead of running the actual calibration routine, the calibration processor calculates the expected arrival time of read data based on the memory latency values entered during EMIF IP generation, resulting in reduced simulation time. Skip calibration mode is recommended for use during system development, because it allows you to focus on interacting with the controller and optimizing your memory access patterns, thus facilitating rapid RTL development.

If you enable Skip Calibration Mode, the interface still performs some memory initialization, sending DRAM Mode Register Set (MRS) commands, or commands to program register code words for RDIMM/LRDIMM, before starting normal operation. These initialization commands are necessary to set up the memory model operation and latencies.