is42s16400f-5tli Integrated Silicon Solution, Inc., is42s16400f-5tli Datasheet - Page 34

• Manufacturer Part Number: is42s16400f-5tli
• Description: 1 Meg Bits X 16 Bits X 4 Banks 64-mbit Synchronous Dynamic Ram
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S16400F, IC42S16400F
IS45S16400F
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
Fig CAP 1 - READ With Auto Precharge interrupted by a READ
34
Fig CAP 2 - READ With Auto Precharge interrupted by a WRITE
Internal States
Internal States
COMMAND
COMMAND
ADDRESS
ADDRESS
BANK m
BANK m
BANK n
BANK n
DQM
CLK
CLK
DQ
DQ
WRITE - AP
BANK n,
BANK n,
Page Active
T0
T0
BANK n
COL a
COL a
NOP
Page Active
CAS Latency - 3 (BANK n)
READ - AP
BANK n
T1
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
READ - AP
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,
CAS latency later. The PRECHARGE to bank n will
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 two clocks prior
to the WRITE command to prevent bus contention. The
PRECHARGE to bank n will begin when the WRITE to
bank m is registered.
WRITE - AP
BANK m,
BANK m,
BANK m
T4
T4
Integrated Silicon Solution, Inc. — www.issi.com
NOP
COL b
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
D
IN
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
RP - BANK m
b+1
Idle
05/29/08
Rev. C