IS42S16128
ISSI ®
Write Cycle (Full Page) Interruption
Using the Burst Stop Command
The IS42S16128 can input data continuously from the
burst start address (a) to location a+255 during a write
cycle in which the burst length is set to full page. The
IS42S16128 repeats the operation starting at the 256th
cycle with data input returning to location (a) and continu-
ing with a+1, a+2, a+3, etc. A burst stop command must
be executed to terminate this cycle. A precharge com-
mand must be executed within the ACT to PRE command
period (tRAS max.) following the burst stop command.
After the period (tWBD) required for burst data input to stop
following the execution of the burst stop command has
elapsed, the write cycle terminates. This period (tWBD) is
zero clock cycles, regardless of the CAS latency.
CLK
COMMAND WRITE A0
I/O
DIN A0 DIN A1 DIN A
READ (CA=A, BANK 0)
CAS latency = 2, 3, burst length = full page
DIN A1
DIN A2
tWBD=0
tRP
BST
PRE 0
INVALID DATA
BURST STOP PRECHARGE (BANK 0)
Don’t Care
Burst Data Interruption Using the
U/LDQM Pins (Read Cycle)
Burst data output can be temporarily interrupted (masked)
during a read cycle using the U/LDQM pins. Regardless
of the CAS latency, two clock cycles (tQMD) after one of the
U/LDQM pins goes HIGH, the corresponding outputs go
to the HIGH impedance state. Subsequently, the outputs
are maintained in the high impedance state as long as
that U/LDQM pin remains HIGH. When the U/LDQM pin
goes LOW, output is resumed at a time tQMD later. This
output control operates independently on a byte basis
with the UDQM pin controlling upper byte output (pins
I/O8-I/O15) and the LDQM pin controlling lower byte
output (pins I/O0 to I/O7).
Since the U/LDQM pins control the device output buffers
only, the read cycle continues internally and, in particular,
incrementing of the internal burst counter continues.
CLK
COMMAND READ A0
UDQM
LDQM
tQMD=2
I/O8-I/O15
DOUT A0
DOUT A2 DOUT A3
HI-Z
HI-Z
I/O0-I/O 7
DOUT A0 DOUT A1
HI-Z
READ (CA=A, BANK 0) DATA MASK (LOWER BYTE)
DATA MASK (UPPER BYTE)
CAS latency = 2, burst length = 4
Integrated Silicon Solution, Inc. — 1-800-379-4774
31
Rev. A
03/13/00