Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
180
UG586 November 30, 2016
Chapter 1:
DDR3 and DDR2 SDRAM Memory Interface Solution
Customizing the Core
The 7 series FPGAs memory interface solution supports several configurations for DDR2 or
DDR3 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
,
, and
.
Table 1-64:
7 Series FPGA Memory Solution Configuration Parameters
Parameter
Description
Options
REFCLK_FREQ
This is the reference clock frequency for
IDELAYCTRLs. This can be set to 200.0 for any
speed grade device. For DDR3 SDRAM designs,
the frequency value is dependent on memory
design frequency and FPGA speed grade. For
more information, see the IDELAYE2 (IDELAY)
and ODELAYE2 (ODELAY) Attribute Summary
table in the
7 Series FPGAs SelectIO™
Resources User Guide
. This parameter
should
not
be changed.
200.0, 300.0, and 400.0
SIM_BYPASS_INIT_CAL
This is the calibration procedure for simulation.
“OFF” is not supported in simulation. “OFF”
must be used for hardware implementations.
“FAST” enables a fast version of read and write
leveling. “SIM_FULL” enables full calibration
but skips the power-up initialization delay.
“SIM_INIT_CAL_FULL” enables full calibration
including the power-up delays.
“OFF”
“SIM_INIT_CAL_FULL”
“FAST”
“SIM_FULL”
nCK_PER_CLK
This is the number of memory clocks per clock.
4, 2 (depends on the PHY to
Controller Clock ratio chosen in the
GUI)
nCS_PER_RANK
This is the number of unique CS outputs per
rank for the PHY.
1, 2
DQS_CNT_WIDTH
This is the number of bits required to index the
DQS bus and is given by
ceil(log
2
(DQS_WIDTH)).
ADDR_WIDTH
This is the memory address bus width. It is
equal to RANK BANK
ROW COL_WIDTH.
BANK_WIDTH
This is the number of memory bank address
bits.
This option is based on the selected
memory device.
CS_WIDTH
This is the number of unique CS outputs to
memory.
This option is based on the selected
MIG tool configuration.