CY7C1325G
Document #: 38-05518 Rev. *D
Page 5 of 16
Single Write Accesses Initiated by ADSP
This access is initiated when the following conditions are
satisfied at clock rise: (1) CE1, CE2, CE3 are all asserted
active, and (2) ADSP is asserted LOW. The addresses
presented are loaded into the address register and the burst
inputs (GW, BWE, and BW[A:B]) are ignored during this first
clock cycle. If the write inputs are asserted active (see Write
Cycle Descriptions table for appropriate states that indicate a
write) on the next clock rise, the appropriate data will be
latched and written into the device. Byte writes are allowed.
During byte writes, BWA controls DQA and BWB controls DQB.
All I/Os are tri-stated during a byte write.Since this is a
common I/O device, the asynchronous OE input signal must
be deasserted and the I/Os must be tri-stated prior to the
presentation of data to DQs. As a safety precaution, the data
lines are tri-stated once a write cycle is detected, regardless
of the state of OE.
Single Write Accesses Initiated by ADSC
This write access is initiated when the following conditions are
satisfied at clock rise: (1) CE1, CE2, and CE3 are all asserted
active, (2) ADSC is asserted LOW, (3) ADSP is deasserted
HIGH, and (4) the write input signals (GW, BWE, and BW[A:B])
indicate a write access. ADSC is ignored if ADSP is active
LOW.
The addresses presented are loaded into the address register
and the burst counter/control logic and delivered to the
memory core. The information presented to DQ[A:D] will be
written into the specified address location. Byte writes are
allowed. During byte writes, BWA controls DQA, BWB controls
DQB. All I/Os are tri-stated when a write is detected, even a
byte write. Since this is a common I/O device, the
asynchronous OE input signal must be deasserted and the
I/Os must be tri-stated prior to the presentation of data to DQs.
As a safety precaution, the data lines are tri-stated once a write
cycle is detected, regardless of the state of OE.
Burst Sequences
The CY7C1325G provides an on-chip two-bit wraparound
burst counter inside the SRAM. The burst counter is fed by
A[1:0], and can follow either a linear or interleaved burst order.
The burst order is determined by the state of the MODE input.
A LOW on MODE will select a linear burst sequence. A HIGH
on MODE will select an interleaved burst order. Leaving
MODE unconnected will cause the device to default to a inter-
leaved burst sequence.
Sleep Mode
The ZZ input pin is an asynchronous input. Asserting ZZ
places the SRAM in a power conservation “sleep” mode. Two
clock cycles are required to enter into or exit from this “sleep”
mode. While in this mode, data integrity is guaranteed.
Accesses pending when entering the “sleep” mode are not
considered valid nor is the completion of the operation
guaranteed. The device must be deselected prior to entering
the “sleep” mode. CEs, ADSP, and ADSC must remain
inactive for the duration of tZZREC after the ZZ input returns
LOW.
.
Interleaved Burst Address Table
(MODE = Floating or VDD)
First
Address
A1, A0
Second
Address
A1, A0
Third
Address
A1, A0
Fourth
Address
A1, A0
00
01
10
11
01
00
11
10
10
11
00
01
11
10
01
00
Linear Burst Address Table (MODE = GND)
First
Address
A1, A0
Second
Address
A1, A0
Third
Address
A1, A0
Fourth
Address
A1, A0
00
01
10
11
01
10
11
00
10
11
00
01
11
00
01
10
ZZ Mode Electrical Characteristics
Parameter
Description
Test Conditions
Min.
Max.
Unit
IDDZZ
Sleep mode standby current
ZZ > VDD – 0.2V
40
mA
tZZS
Device operation to ZZ
ZZ > VDD – 0.2V
2tCYC
ns
tZZREC
ZZ recovery time
ZZ < 0.2V
2tCYC
ns
tZZI
ZZ Active to sleep current
This parameter is sampled
2tCYC
ns
tRZZI
ZZ Inactive to exit sleep current
This parameter is sampled
0
ns