Table 8-2: FPGA-to-HPS SDRAM Port Utilization
Write Data
Read Data
Command
Bus Protocol
1
1
2
(1)
32- or 64-bit AXI
2
(2)
2
(2)
2
(1)
128-bit AXI
4
(2)
4
(2)
2
(1)
256-bit AXI
1
1
1
32- or 64-bit Avalon-MM
2
2
1
128-bit Avalon-MM
4
4
1
256-bit Avalon-MM
1
0
1
32- or 64-bit Avalon-MM write-only
2
0
1
128-bit Avalon-MM write-only
4
0
1
256-bit Avalon-MM write-only
0
1
1
32- or 64-bit Avalon-MM read-only
0
2
1
128-bit Avalon-MM read-only
0
4
1
256-bit Avalon-MM read-only
Notes to Table:
1. Because the AXI protocol allows simultaneous read and write commands to be issued, two SDRAM
control ports are required to form an AXI interface.
2. Because the native size of the data ports is 64 bits, extra read and write ports are required to form an AXI
interface.
Memory Controller Architecture
The SDRAM controller consists of an MPFE, a single-port controller, and an interface to the CSRs. The
following figure shows a block diagram of the SDRAM controller portion of the SDRAM controller subsystem.
SDRAM Controller Subsystem
Altera Corporation
cv_54008
Memory Controller Architecture
8-4
2013.12.30