Fabric DDR Subsystem
Microsemi ProprietaryUG0446 User Guide Revision 7.0
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The FDDR subsystem accepts data transfer requests from AXI or AHB interfaces. Any read or write
transactions to the DDR memories can occur through the AXI or AHBL masters in the FPGA fabric
through DDR_FIC interface.
Note:
The maximum DDR3 data rate supported by FDDR is 333MHz/667Mbps. Therefore, Write Leveling is
not mandatory and the interface works if the board layout includes length matching and follows
SmartFusion2 and IGLOO2 Board Design Guidelines Application Note
. For Read Leveling, Libero SOC
auto-generates pre-defined static delay ratios for FDDR initialization. These delay values are sufficient if
the board layout follows the SmartFusion2/IGLOO2 board-level guidelines.
4.2
Memory Configurations
The SmartFusion2/IGLOO2 FDDR subsystem supports a wide range of common memory types,
configurations, and densities, as shown in the following table. If SECDED mode is enabled in the FDDR
controller, the external memory module must be connected to the following:
•
Data lines FDDR_DQ_ECC[3:0] when data width is x32
•
Data lines FDDR_DQ_ECC[1:0] when data width is x16
•
Data line FDDR_DQ_ECC[0] when data width is x8
4.3
Performance
The following table shows the maximum data rates supported by the FDDR subsystem for supported
memory types. For more information on DDR Speeds, Refer to the "DDR Memory Interface
Characteristics" section in
DS0128: IGLOO2 and SmartFusion2 Datasheet
Table 125 •
Supported Memory (DDR2, DDR3, and LPDDR1) Configurations
Memory
Depth
Width
Width (in SECDED
Mode)
SmartFusion2/IGLOO2 Devices
M2S150
(FCV484)
M2S050/M2GL050
(FG896)
M2S150/M2GL150
(FC1152)
128M or
Less
x32
x36
–
√
√
x16
x18
√
√
√
x8
x9
√
–
√
256M
x32
x36
–
√
√
x16
x18
√
√
√
x8
x9
√
–
√
512M
x32
x36
–
√
√
x16
x18
√
√
√
x8
x9
√
–
√
1G
x32
x36
–
√
√
x16
x18
√
√
√
x8
x9
√
–
√
Table 126 •
DDR Speeds
Memory Type
Maximum Data Rate (Mbps)
LPDDR1
400 Mbps (200 MHz)
DDR2
667 Mbps (333 MHz)
DDR3
667 Mbps (333 MHz)