User manual

Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 293
UG585 (v1.11) September 27, 2016
Chapter 10: DDR Memory Controller
10.1.3 Notices
7z007s and 7z010 CLG225 Devices
All devices support the 32- and 16-bit data bus width options except the 7z007s single core and
7z010 dual core CLG225 devices. These CLG225 devices only support the 16-bit data bus width, not
the 32-bit bus.
10.1.4 Interconnect
The four AXI_HP interfaces are multiplexed down, in pairs, and are connected to ports 2 and 3 as
shown in Figure 10-2. These ports are commonly configured for high bandwidth traffic. The path
from these four interfaces to the DDR include two ports on the DDR memory port arbiter. The
interconnect switch arbitrates back-and-forth between each of the two ports. Read and write
channels operate separately. The arbitration in the bridge can be affected by the QoS signals from
each PL interface. A requestor with a higher QoS value is given preferential treatment by the
interconnect bridge. Arbitration is priority based using QoS as priority. In the event of a tie, an LRG
scheme is used to break the tie.
The L2-cache is connected to port 0 and is used to serve the CPUs and the ACP interface to the PL.
This port is commonly configured for low-latency. The other masters on the AXI interconnect are
connected to port 1.
X-Ref Target - Figure 10-2
Figure 10-2: DDRC System Viewpoint
UG585_c10_02_032012
to OCM
From Central
Interconnect
High Performance
AXI Controllers
(AXI_HP)
AXI_HP
Path to DDR
PL
64-bit
M0
FIFO
M1 M2 M3
S0
S1 S2
M0 M1 M2
S3
FIFOFIFO
From L2
Cache
FIFO
AXI_HP
to DDR
Interconnect
S3 S2 S1 S0
DDR Memory Controller