is42s16400b1 Integrated Silicon Solution, Inc., is42s16400b1 Datasheet - Page 21

• Manufacturer Part Number: is42s16400b1
• Description: 1 Meg Bits X 16 Bits X 4 Banks 64-mbit Synchronous Dynamic Ram - Integrated Silicon Solution, Inc
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S16400B1
same bank. The PRECHARGE command should be issued
x cycles before the clock edge at which the last desired
data element is valid, where x equals the CAS latency
minus one. This is shown in the READ to PRECHARGE
diagram for each possible CAS latency; data element n +
3 is either the last of a burst of four or the last desired of a
longer burst. Following the PRECHARGE command, a
subsequent command to the same bank cannot be issued
until t
hidden during the access of the last data element(s).
In the case of a fixed-length burst being executed to
completion, a PRECHARGE command issued at the
optimum time (as described above) provides the same
operation that would result from the same fixed-length
burst with auto precharge. The disadvantage of the
CAS Latency
Integrated Silicon Solution, Inc. — www.issi.com —
Rev. A
12/09/03
RP
is met. Note that part of the row precharge time is
COMMAND
COMMAND
CLK
CLK
DQ
DQ
READ
READ
T0
T0
xx x x
CAS Latency - 2
NOP
NOP
CAS Latency - 3
T1
T1
t
LZ
1-800-379-4774
t
AC
xx
xx
PRECHARGE command is that it requires that the com-
mand and address buses be available at the appropriate
time to issue the command; the advantage of the
PRECHARGE command is that it can be used to truncate
fixed-length or full-page bursts.
Full-page READ bursts can be truncated with the BURST
TERMINATE command, and fixed-length READ bursts
may be truncated with a BURST TERMINATE command,
provided that auto precharge was not activated. The
BURST TERMINATE command should be issued x cycles
before the clock edge at which the last desired data
element is valid, where x equals the CAS latency minus
one. This is shown in the READ Burst Termination
diagram for each possible CAS latency; data element n +
3 is the last desired data element of a longer burst.
NOP
NOP
T2
T2
D
OUT
t
t
OH
LZ
t
AC
x
x
x
x
NOP
T3
T3
D
DON'T CARE
UNDEFINED
OUT
t
OH
T4
ISSI
21
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