AS4C16M16D1
Pin Descriptions
Table 2. Pin Details
Symbol
CK,
Type
Description
are driven by the system clock. All SDRAM input signals
Input
Differential Clock: CK,
CK
CK
are sampled on the positive edge of CK. Both CK and
counter and controls the output registers.
increment the internal burst
CK
CKE
Input
Clock Enable: CKE activates (HIGH) and deactivates (LOW) the CK signal. If CKE
goes low synchronously with clock, the internal clock is suspended from the next clock
cycle and the state of output and burst address is frozen as long as the CKE remains
low. When all banks are in the idle state, deactivating the clock controls the entry to
the Power Down and Self Refresh modes.
BA0, BA1
A0-A12
Input
Input
Bank Activate: BA0 and BA1 define to which bank the BankActivate, Read, Write, or
BankPrecharge command is being applied.
Address Inputs: A0-A12 are sampled during the BankActivate command (row
address A0-A12) and Read/Write command (column address A0-A8 with A10 defining
Auto Precharge).
Input
Input
Chip Select:
enables (sampled LOW) and disables (sampled HIGH) the
CS
command decoder. All commands are masked when
CS
is sampled HIGH.
CS
CS
provides for external bank selection on systems with multiple banks. It is considered
part of the command code.
Row Address Strobe: The
signal defines the operation commands in
RAS
signals and is latched at the positive edges of CK.
RAS
conjunction with the
and
WE
CAS
are asserted "LOW" and
When
and
is asserted "HIGH," either the
CAS
RAS
CS
BankActivate command or the Precharge command is selected by the
signal.
WE
is asserted "HIGH," the BankActivate command is selected and the
When the
WE
bank designated by BA is turned on to the active state. When the
is asserted
WE
"LOW," the Precharge command is selected and the bank designated by BA is
switched to the idle state after the precharge operation.
Input
Input
Column Address Strobe: The
signal defines the operation commands in
CAS
signals and is latched at the positive edges of CK.
is asserted "LOW," the column access is started
CAS
WE
conjunction with the
and
RAS
WE
CS
When
RAS
by asserting
is held "HIGH" and
"LOW." Then, the Read or Write command is selected by asserting
CAS
"HIGH" or “LOW”.
WE
Write Enable: The
signal defines the operation commands in conjunction with
WE
signals and is latched at the positive edges of CK. The
the
and
input
WE
RAS
CAS
is used to select the BankActivate or Precharge command and Read or Write
command.
LDQS,
UDQS
Input /
Output
Bidirectional Data Strobe: Specifies timing for Input and Output data. Read Data
Strobe is edge triggered. Write Data Strobe provides a setup and hold time for data
and DQM. LDQS is for DQ0~7, UDQS is for DQ8~15.
LDM,
UDM
Input
Data Input Mask: Input data is masked when DM is sampled HIGH during a write
cycle. LDM masks DQ0-DQ7, UDM masks DQ8-DQ15.
DQ0 - DQ15 Input /
Output
Data I/O: The DQ0-DQ15 input and output data are synchronized with the positive
edges of CK and
The I/Os are byte-maskable during Writes.
CK
Alliance Memory, lnc. Confidential
4
Rev. 1.1
Sep. /2011
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
