Fabric DDR Subsystem
Microsemi ProprietaryUG0446 User Guide Revision 7.0
134
4
Fabric DDR Subsystem
The FDDR is a hardened ASIC block for interfacing the DDR2, DDR3, and LPDDR1 memories. The
FDDR subsystem is used to access DDR memories for high-speed data transfers. The FDDR subsystem
includes the DDR memory controller, DDR PHY, and arbitration logic to support multiple masters.
FPGA fabric masters communicate with the DDR memories interfaced to the FDDR subsystem through
AXI or AHB interfaces.
4.1
Features
•
Integrated on-chip DDR memory controller and PHY
•
Configurable to support LPDDR1, DDR2, and DDR3 memory devices
•
Up to 667 Mbps (333 MHz DDR) performance
•
Supports memory densities up to 4 GB
•
Supports 8/16/32-bit data bus width modes
•
Supports a maximum of 8 memory banks
•
Supports single rank memory
•
Single error correction and double error detection (SECDED) enable or disable feature
•
Supports DRAM burst lengths of 4, 8, or 16, depending on the Bus-width mode and DDR type
configuration
•
Support for sequential and interleaved burst ordering
•
Programs internal control for ZQ short calibration cycles for DDR3 configurations
•
Supports dynamic scheduling to optimize bandwidth and latency
•
Supports self refresh entry and exit on command
•
Supports deep power-down entry and exit on command
•
Flexible address mapper logic to allow application specific mapping of row, column, bank, and rank
bits
•
Configurable support for 1T or 2T timing on the DDR SDRAM control signals
•
Supports autonomous DRAM power-down entry and exit caused by lack of transaction arrival for
programmable time
•
Advanced power-saving design includes toggling of command, address, and data pins
The system level block diagram of the FDDR subsystem is shown in the following illustration.
Figure 74 •
System Level FDDR Block Diagram
AHB Bus Matrix
Fabric
FDDR
SmartFusion2/IGLOO2
MSS/HPMS
DDR_FIC
AXI
Transaction
Controller
APB
Master
16-Bit APB
DDR
SDRAM
DDR
Controller
APB Config
Register
64-Bit AXI/
Single 32-Bit AHBL/
Dual 32-Bit AHBL
Note:
Blocks and arrows marked in grey, only in SmartFusion2 MSS. Rest are all similar in MSSHPMS.
AXI/AHB
Master
FIC_0
FIC_2
ARM Cortex-M3
Processor
S D I
Cache Controller
S D IC
FIC_1
D
D
R
P
H
Y
D
D
R
I
O