External Memory Interfaces Intel® Agilex™ FPGA IP User Guide

ID 683216
Date 10/04/2021
Public

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3.1.4.1. Considerations for Designing DDR4 x72 Interface Together with an AVST x8/x16/x32 Configuration Scheme

The AVST x8 configuration scheme uses the dedicated SDM I/O pins and does not impact the number of DDR4 x72 interfaces that can be implemented on the device. An AVST x32 configuration scheme uses all four of the I/O lanes in the top sub-bank in Bank 3A. This breaks the contiguity requirement and reduces the maximum number of DDR4 x72 interfaces that can be supported on the device.

However, the AVST x16 configuration scheme only uses three I/O Lanes. I/O Lane 2 in the top sub-bank in Bank 3A is available for EMIF purposes and maintains the contiguity requirement. This I/O Lane can be used as a DQ Lane for EMIF purposes.

Figure 25. Pin Assignment in Top Sub-bank in Bank 3A for AVST x16 Configuration Scheme

To implement a DDR4 x72 interface using the top sub-bank in Bank 3A together with an AVST x16 configuration scheme, you must use the address/command scheme with four IO Lanes. The following figure shows the I/O lane assignment for implementing a DDR4 x 72 interface in such a scenario.

Figure 26. I/O Lane Assignment for Implementing AVST x16 and DDR4 x72 Interface Using Bank 3A

The following table shows the maximum number of DDR4 x72 interfaces that can be supported with different AVST configuration schemes.

Table 5.  DDR x72 EMIF With AVST and Address/Command Scheme with 4 I/O Lanes
Device/Package 1× DDR4 x72 2× DDR4 x72 3× DDR4 x72 4× DDR4 x72 6× DDR4 x72 8× DDR4 x72
AGF014/AGF012, R24A/R24B AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16 N/A N/A
AGF027/AGF022, R24C AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16 N/A N/A
AGF027/AGF022, R25A AVST 8, 16, 32 AVST 8, 16, 32 N/A N/A N/A N/A
AGF027/AGF022, R31C AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGI027/AGI022, R29A AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGI027/AGI022, R31B AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGF023, R25A AVST 8, 16, 32 AVST 8, 16 N/A N/A N/A N/A
Table 6.  DDR x72 EMIF With AVST and Address/Command Scheme with 3 I/O Lanes
Device/Package 1× DDR4 x72 2× DDR4 x72 3× DDR4 x72 4× DDR4 x72 6× DDR4 x72 8× DDR4 x72
AGF014/AGF012, R24A/R24B AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGF027/AGF022, R24C AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGF027/AGF022, R25A AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 N/A N/A
AGF027/AGF022, R31C AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGI027/AGI022, R29A AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGI027/AGI022, R31B AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 AVST 8 N/A N/A
AGF023, R25A AVST 8, 16, 32 AVST 8, 16, 32 AVST 8, 16, 32 N/A N/A N/A