Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
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UG586 November 30, 2016
Chapter 4:
LPDDR2 SDRAM Memory Interface Solution
Similarly, when the
wr_data_en
signal is asserted, the Memory Controller is processing a
write command request.
When NORM ordering mode is enabled, the Memory Controller reorders received requests
to optimize throughput between the FPGA and memory device. The data is returned to the
user design in the order processed, not the order received. The user design can identify the
specific request being processed by monitoring
rd_data_addr
and
wr_data_addr
.
These fields correspond to the
data_buf_addr
supplied when the user design submits
the request to the native interface. Both of these scenarios are depicted in
The native interface is implemented such that the user design must submit one request at
a time and, thus, multiple requests must be submitted in a serial fashion. Similarly, the core
must execute multiple commands to the memory device one at a time. However, due to
pipelining in the core implementation, read and write requests can be processed in parallel
at the native interface.
User ZQ
See
for the UI. The feature is identical in the native interface.
Customizing the Core
The 7 series FPGAs memory interface solution supports several configurations for LPDDR2
SDRAM devices. The specific configuration is defined by Verilog parameters in the top-level
of the core. As per the OOC flow, none of the parameter values are passed down to the user
design RTL file from the example design top RTL file. So, any design related parameter
change is not reflected in the user design logic. The MIG tool should be used to regenerate
a design when parameters need to be changed. The parameters set by the MIG tool are
summarized in
.