Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
184
UG586 November 30, 2016
Chapter 1:
DDR3 and DDR2 SDRAM Memory Interface Solution
tRCD
This is the ACTIVE-to-READ or -WRITE
command delay.
This value, in picoseconds, is based
on the device selection in the MIG
tool.
tREFI
This is the average periodic refresh interval
for memory.
This value, in picoseconds, is based
on the device selection in the MIG
tool.
tRFC
This is the REFRESH-to-ACTIVE or
REFRESH-to-REFRESH command interval.
This value, in picoseconds, is based
on the device selection in the MIG
tool.
tRP
This is the PRECHARGE command period.
This value, in picoseconds, is based
on the device selection in the MIG
tool.
tRTP
This is the READ-to-PRECHARGE command
delay.
This value, in picoseconds, is based
on the device selection in the MIG
tool.
tWTR
This is the WRITE-to-READ command delay.
This value, in picoseconds, is based
on the device selection in the MIG
tool.
tZQI
This is the ZQ short calibration interval. This
value is system dependent and should be
based on the expected rate of change of
voltage and temperature in the system.
Consult the memory vendor for more
information on ZQ calibration.
This value is set in nanoseconds. Set
to 0, if the user manages this
function.
tZQCS
This is the timing window to perform the
ZQCS command in DDR3 SDRAM.
This value, in CK, is based on the
device selection in the MIG tool.
nAL
This is the additive latency in memory clock
cycles.
0
CL
This is the read CAS latency. The available
option is frequency dependent in the MIG
tool.
DDR3: 5, 6, 7, 8, 9, 10, 11
DDR2: 3, 4, 5, 6
CWL
This is the write CAS latency. The available
option is frequency dependent in the MIG
tool.
DDR3: 5, 6, 7, 8
BURST_TYPE
This is an option for the ordering of
accesses within a burst.
“Sequential”
“Interleaved”
RST_ACT_LOW
This is the active-Low or active-High reset.
This is set to 1 when System Reset Polarity
option is selected as active-Low and set to 0
when the option is selected as active-High.
0, 1
IBUF_LPWR_MODE
This option enables or disables the
low-power mode for the input buffers.
“ON”
“OFF”
IODELAY_HP_MODE
This option enables or disables the IDELAY
high-performance mode.
“ON”
”OFF”
Table 1-65:
Embedded 7 Series FPGAs Memory Solution Configuration Parameters
(Cont’d)
Parameter
Description
Options