User guide

3–8 Chapter 3: Parameter Settings
ALTMEMPHY Parameter Settings
External Memory Interface Handbook Volume 3 December 2010 Altera Corporation
Section II. DDR3 SDRAM Controller with ALTMEMPHY IP User Guide
Memory auto self refresh
method
Manual SR
reference (SRT) or
ASR enable
(Optional)
—
Sets the auto self-refresh method for the memory
device. The DDR3 SDRAM Controller with ALTMEMPHY
IP currently does not support the ASR option that you
need for extended temperature memory self-refresh.
Memory self refresh range
Normal or
Extended
—
Determines the temperature range for self refresh. You
need to also use the optional auto self refresh option
when using this option. The Altera controller currently
does not support the extended temperature self-refresh
operation.
Table 3–4. DDR3 SDRAM Initialization Options (Part 3 of 3)
Parameter Name Range Units Description
Table 3–5. DDR3 SDRAM Timing Parameter Settings (Part 1 of 3) (Note 1)
Parameter Name Range Units Description
Time to hold memory reset
before beginning calibration
0–1000000 µs
Minimum time to hold the reset after a power cycle
before issuing the MRS commands during the DDR3
SDRAM device initialization process.
t
INIT
0.001–
1000
µs
Minimum memory initialization time. After reset, the
controller does not issue any commands to the
memory during this period.
t
MRD
2–39 ns
Minimum load mode register command period. The
controller waits for this period of time after issuing a
load mode register command before issuing any other
commands.
t
MRD
is specified in ns in the DDR3 SDRAM
high-performance controller and in terms of t
CK
cycles
in Micron's device datasheet. Convert t
MRD
to ns by
multiplying the number of cycles specified in the
datasheet times t
CK
, where t
CK
is the memory operation
frequency and not the memory device's t
CK
.
t
RAS
8–200 ns
Minimum active to precharge time. The controller waits
for this period of time after issuing an active command
before issuing a precharge command to the same bank.
t
RCD
4–65 ns
Minimum active to read-write time. The controller does
not issue read or write commands to a bank during this
period of time after issuing an active command.
t
RP
4–65 ns
Minimum precharge command period. The controller
does not access the bank for this period of time after
issuing a precharge command.
t
REFI
1–65534 µs
Maximum interval between refresh commands. The
controller performs regular refresh at this interval
unless user-controlled refresh is turned on.
t
RFC
14–1651 ns
Minimum autorefresh command period. The length of
time the controller waits before doing anything else
after issuing an auto-refresh command.
t
WR
4–65 ns
Minimum write recovery time. The controller waits for
this period of time after the end of a write transaction
before issuing a precharge command.