EtronTech
EM636327
14 Burst Stop command
(RAS# = "H", CAS# = "H", WE# = "L", DSF = "L")
The Burst Stop command is used to terminate either fixed-length or full-page bursts. This
command is only effective in a read/write burst without the auto precharge function. The terminated
read burst ends after a delay equal to the CAS# latency (refer to the following figure). The
termination of a write burst is shown in the following figure.
T0
T1
T2
T3
T4
T5
T6
T7
T8
CLK
READ A
NOP
NOP
NOP
COMMAND
NOP
NOP
Burst Stop
DOUT A
NOP
NOP
The burst ends after a delay equal to the CAS# latency.
CAS# latency=1
DOUT A
DOUT A
DOUT A
0
1
2
3
t
, DQ's
CK1
CAS# latency=2
, DQ's
DOUT A
DOUT A
DOUT A
2
DOUT A
3
0
1
t
CK2
CAS# latency=3
DOUT A
0
DOUT A
DOUT A
DOUT A
3
1
2
t
, DQ's
CK3
Termination of a Burst Read Operation
¡ Ö
4, CAS# Latency = 1, 2, 3)
(Burst Length
T0
T1
T2
T3
T4
T5
T6
T7
T8
CLK
NOP
NOP
NOP
COMMAND
NOP
WRITE A
NOP
Burst Stop
don't care
NOP
NOP
CAS# latency=1, 2, 3
DQ's
DIN A
DIN
A
DIN A
2
1
0
Input data for the Write is masked.
Termination of a Burst Write Operation
(Burst Length = X, CAS# Latency = 1, 2, 3)
15 Device Deselect command
(CS# = "H")
The Device Deselect command disables the command decoder so that the RAS#, CAS#, WE#
and Address inputs are ignored, regardless of whether the CLK is enabled. This command is similar
to the No Operation command.
16 AutoRefresh command (refer to Figures 3 & 4 in Timing Waveforms)
(RAS# = "L", CAS# = "L", WE# = "H", DSF = "L", CKE = "H", BS, A0-A9 = Don't care)
The AutoRefresh command is used during normal operation of the SGRAM and is analogous to
CAS#-before-RAS# (CBR) Refresh in conventional DRAMs. This command is non-persistent, so it
must be issued each time a refresh is required. The addressing is generated by the internal refresh
controller. This makes the address bits a "don't care" during an AutoRefresh command. The internal
refresh counter increments automatically on every auto refresh cycle to all of the rows. The refresh
operation must be performed 2048 times within 32ms. The time required to complete the auto
refresh operation is specified by tRC(min.). To provide the AutoRefresh command, both banks need
to be in the idle state and the device must not be in power down mode (CKE is high in the previous
cycle). This command must be followed by NOPs until the auto refresh operation is completed. The
precharge time requirement, tRP(min), must be met before successive auto refresh operations are
performed.
Preliminary
1998
December
17
ETRON [ ETRON TECHNOLOGY, INC. ]
