is42s16800-7tli Integrated Silicon Solution, Inc., is42s16800-7tli Datasheet - Page 49

• Manufacturer Part Number: is42s16800-7tli
• Description: 16m X 8, 8m X16 128mb Synchronous Dram
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S81600, IS42S16800
BURST READ/SINGLE WRITE
The burst read/single write mode is entered by programming
the write burst mode bit (M9) in the mode register to a logic
1. In this mode, all WRITE commands result in the access
of a single column location (burst of one), regardless of
the programmed burst length. READ commands access
columns according to the programmed burst length and
sequence, just as in the normal mode of operation (M9
= 0).
CONCURRENT AUTO PRECHARGE
An access command (READ or WRITE) to another bank
while an access command with auto precharge enabled is
executing is not allowed by SDRAMs, unless the SDRAM
supports CONCURRENT AUTO PRECHARGE. ISSI
READ With Auto Precharge interrupted by a READ
READ With Auto Precharge interrupted by a WRITE
Integrated Silicon Solution, Inc. — www.issi.com
Rev. 00A
08/06/08
COMMAND
Internal States
COMMAND
Internal States
ADDRESS
ADDRESS
BANK m
BANK m
BANK n
BANK n
DQM
CLK
CLK
DQ
DQ
READ - AP
BANK n,
Page Active
BANK n
T0
T0
COL a
NOP
Page Active
CAS Latency - 3 (BANK n)
BANK n,
READ - AP
COL a
T1
BANK n
T1
NOP
Page Active
Page Active
READ with Burst of 4
READ with Burst of 4
CAS Latency - 3 (BANK n)
T2
T2
NOP
NOP
BANK n,
READ - AP
COL b
BANK m
T3
T3
NOP
D
OUT
a
CAS Latency - 3 (BANK m)
SDRAMs support CONCURRENT AUTO PRECHARGE.
Four cases where CONCURRENT AUTO PRECHARGE
occurs are defined below.
READ with Auto Precharge
1. Interrupted by a READ (with or without auto precharge):
2.Interrupted by a WRITE (with or without auto precharge):
Interrupt Burst, Precharge
A READ to bank m will interrupt a READ on bank n,
begin when the READ to bank m is registered.
A WRITE to bank m will interrupt a READ on bank n
when registered.DQM should be used three clocks prior
to the WRITE command to prevent bus contention. The
CAS latency later. The PRECHARGE to bank n will
PRECHARGE to bank n will begin when the WRITE to
bank m is registered.
WRITE - AP
BANK m,
BANK m
T4
T4
NOP
COL b
D
D
IN
t
OUT
RP - BANK n
READ with Burst of 4
b
a
Interrupt Burst, Precharge
WRITE with Burst of 4
T5
T5
D
NOP
NOP
D
IN
OUT
t
b+1
RP - BANK n
a+1
T6
T6
D
NOP
NOP
IN
D
OUT
b+2
b
DON'T CARE
DON'T CARE
Idle
T7
T7
D
NOP
D
NOP
IN
Write-Back
Precharge
OUT
b+3
t
t
RP - BANK m
DPL - BANK m
b+1
Idle
49