SDRAM
AS4SD4M16
Austin Semiconductor, Inc.
with AUTO PRECHARGE. The disadvantage of the may be truncated with a BURST TERMINATE command,
PRECHARGE command is that it requires that the command provided that AUTO PRECHARGE was not activated. The
and address buses be available at the appropriate time to issue BURST TERMINATE command should be issued x cycles
the command; the advantage of the PRECHARGE command is before the clock edge at which the last desired data element is
that it can be used to truncate fixed-length or full-page bursts. valid, where x equals the CAS latency minus one. This is shown
Full-page READ bursts can be truncated with the in Figure 12 for each possible CAS latency; data element n + 3
BURST TERMINATE command, and fixed-length READ bursts is the last desired data element of a longer burst.
T6
T0
T1
T2
T3
T4
T5
CLK
BURST
TERMINATE
NOP
READ
NOP
NOP
NOP
NOP
COMMAND
X = 1 cycles
BANK,
COL n
ADDRESS
DQ
DOUT
n+1
DOUT
n+3
DOUT
n
DOUT
n+2
CAS Latency = 2
T6
T7
T0
T1
T2
T3
T4
T5
CLK
COMMAND
ADDRESS
DQ
BURST
READ
NOP
NOP
NOP
NOP
NOP
NOP
TERMINATE
X = 2 cycles
BANK,
COL n
DOUT
n+2
DOUT
n
DOUT
n+1
DOUT
n+3
CAS Latency = 3
DON’T CARE
NOTE: DQM is LOW.
Figure 12
TERMINATING A READ BURST
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
AS4SD4M16
Rev. 1.5 10/01
18
AUSTIN [ AUSTIN SEMICONDUCTOR ]
