Rev. 0.2 / Dec. 2008 8
HMT164S6AFP(R)6C
HMT112S6AFP(R)6C
HMT125S6AFP(R)8C
2.2 Input/Output Functional Description
Symbol Type Polarity Function
CK0/CK0
CK1/CK1Input Cross point
The system clock inputs. All address and comman d l ines are sampled on the cross
point of the rising edge of CK and f all ing edge of CK . A Dela y Locked Loop (DLL) cir-
cuit is driven from the clock inputs and output timing for read operations is synchro-
nized to the input clock.
CKE[1:0] Input 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 Po wer Down mode or the Self
Refresh mode.
S[1:0] Input 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 com-
mands are ignored but previous operations continue. Rank 0 is selected by S0; Rank
1 is selected by S1.
RAS, CAS, WE Input Active Low When sampled at the cross point of the rising edge of CK and falling edge of CK, sig-
nals CAS, RAS, and WE define the operation to be executed by the SDRAM.
BA[2:0] Input - Selects which DDR3 SDRAM internal bank of eight is activated.
ODT[1:0] Input Active High Assert s on-die termination for DQ, DM, DQS, and DQS signals if enabled via the
DDR3 SDRAM mode register.
A[9:0], A10/AP,
A11, A12/BC,
A[15:13] Input -
During a Bank Ac tivate 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 or
Write c ommand cycle, def in e s t h e co lumn address when sampled at the cross point
of the rising edge of CK and falli ng 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 precharged reg ardless of the state o f BA0-
BAn inputs. If AP is low, then BA0-BAn are used to define which bank to precharge.
A12(BC) is sampled during READ and WRITE commands to determine if burst chop
(on-thefly) will be performed (HIGH, no burst chop; LOW, burst chopped)
DQ[63:0] In/Out - Data Input/Output pins.
DM[7:0] Input Active High The data write masks, associated wi th one data byte. In Write mode, DM operates
as a byte mask by allowing input d a ta to be written if it is low but blocks the write
operation if it is high. In Read mode, DM lines have no effect.
DQS[7:0],
DQS[7:0] In/Out Cross Point
The data strobes, associated with one data byte, sourced with data transfers. In
Write mode, th e data str obe is sour ced by t he contr oller an d is cent er ed in the da ta
window . In R ead mode, the data stro be is sourced by the DDR3 SDRAMs and is sent
at the leading edge of the data window . DQS signals are complements, and timing is
relative to the crosspoint of respective DQS and DQS.