APCPCWM_4828539:WP_0000005WP_0000005
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Rev. 1.2 / Jul. 2010
6
Input/Output Functional Descriptions
Symbol
Type
Polarity
Function
CK0/CK0
CK1/CK1
IN
Cross Point
The system clock inputs. All address and command lines are sampled on the cross point
of the rising edge of CK and falling edge of CK. A Delay Locked Loop (DLL) circuit is
driven from the clock inputs and output timing for read operations is synchronized to the
input clock.
CKE[1:0]
IN
Active
High
Activates the DDR3 SDRAM CK signal when high and deactivates the CK signal when
low. By deactivating the clocks, CKE low initiates the Power Down mode or the Self
Refresh mode.
S[1:0]
IN
Active
Low
Enables the associated DDR3 SDRAM command decoder when low and disables the
command decoder when high. When the command decoder is disabled, new commands
are ignored but previous operations continue. Rank 0 is selected by S0; Rank 1 is
selected by S1.
ODT[1:0]
IN
Active
High
Asserts on-die termination for DQ, DM, DQS, and DQS signals if enabled via the DDR3
SDRAM mode register.
RAS, CAS, WE
IN
Active
Low
When sampled at the cross point of the rising edge of CK, signals CAS, RAS, and WE
define the operation to be executed by the SDRAM.
V
REFDQ
V
REFCA
Supply
Reference voltage for SSTL15 inputs.
BA[2:0]
IN
—
Selects which SDRAM internal bank
of eight is activated.
A[9:0],
A10/AP,
A11,
A12/BC
A[15:13]
IN
—
During a Bank Activate command cycle, defines the row address when sampled at the
cross point of the rising edge of CK and falling edge of CK. During a Read of Write com-
mand cycle, defines the column address when sampled at the cross point of the rising
edge of CK and falling edge of CK. In addition to the column address, AP is used to
invoke autoprecharge operation at the end of the burst read or write cycle. If AP is high
autoprecharge is selected and BA0-BAn defines the bank to be precharged. If AP is low,
autoprecharge is disabled. During a Precharge command cycle, AP is used in conjunction
with BA0-BAn to control which bank(s) to precharge. If AP is high, all banks will be pre-
charged regardless of the state of BA0-BAn inputs. If AP is low, then BA0-BAn are used
to define which bank to precharge. A12(BC) is samples during READ and WRITE com-
mands to determine if burst chop (on-the-fly) will be performed (HIGH, no burst chop:
LOW, burst chopped).
DQ[63:0]
I/O
—
Data Input/Output pins.
DM[7:0]
IN
Active
High
The data write masks, associated with one data byte. In Write mode, DM operates as a
byte mask by allowing input data to be written if it is low but blocks the write operation
if it is high. In Read mode, DM lines have no effect.
V
DD
, V
DDSPD
V
SS
Supply
Power supplies for core, I/O, Serial Presence Detect, and ground for the module.
DQS[7:0],
DQS[7:0]
I/O
Cross Point
The data strobes, associated with one data byte, sourced with data transfers. In Write
mode, the data strobe is sourced by the controller and is centered in the data window.
In Read mode, the data strobe is sourced by the DDR3 SDRAMs and is sent at the lead-
ing edge of the data window. DQS signals are complements, and timing is relative to the
crosspoint of respective DQS and DQS.
SA[1:0]
IN
—
These signals are tied at the system planar to either V
SS
or V
DDSPD
to configure the
serial SPD EEPROM address range.
B48614/178.104.2.80/2010-07-08 11:46
