CY7C1355C
CY7C1357C
Document #: 38-05539 Rev. *E
Page 9 of 28
precaution, DQs and DQP
X
are automatically tri-stated during
the data portion of a write cycle, regardless of the state of OE.
Burst Write Accesses
The CY7C1355C/CY7C1357C has an on-chip burst counter
that allows the user the ability to supply a single address and
conduct up to four Write operations without reasserting the
address inputs. ADV/LD must be driven LOW in order to load
the initial address, as described in the Single Write Access
section above. When ADV/LD is driven HIGH on the subse-
quent clock rise, the Chip Enables (CE
1
, CE
2
, and CE
3
) and
WE inputs are ignored and the burst counter is incremented.
The correct BW
X
inputs must be driven in each cycle of the
burst write, in order to write the correct bytes of data.
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. CE
1
, CE
2
, and CE
3
, must remain inactive
for the duration of t
ZZREC
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
I
DDZZ
Sleep mode standby current
ZZ > V
DD
– 0.2V
50
mA
t
ZZS
Device operation to ZZ
ZZ > V
DD
– 0.2V
2t
CYC
ns
t
ZZREC
ZZ recovery time
ZZ < 0.2V
2t
CYC
ns
t
ZZI
ZZ active to sleep current
This parameter is sampled
2t
CYC
ns
t
RZZI
ZZ Inactive to exit sleep current
This parameter is sampled
0
ns
Truth Table
[2, 3, 4, 5, 6, 7, 8]
Operation
Address
Used
CE
1
CE
2
CE
3
ZZ
ADV/LD WE BW
X
OE CEN CLK
DQ
Deselect Cycle
None
H
X
X
L
L
X
X
X
L
L->H
Tri-State
Deselect Cycle
None
X
X
H
L
L
X
X
X
L
L->H
Tri-State
Deselect Cycle
None
X
L
X
L
L
X
X
X
L
L->H
Tri-State
Continue Deselect Cycle
None
X
X
X
L
H
X
X
X
L
L->H
Tri-State
READ Cycle (Begin Burst)
External
L
H
L
L
L
H
X
L
L
L->H Data Out (Q)
READ Cycle (Continue Burst)
Next
X
X
X
L
H
X
X
L
L
L->H Data Out (Q)
NOP/DUMMY READ (Begin Burst)
External
L
H
L
L
L
H
X
H
L
L->H
Tri-State
DUMMY READ (Continue Burst)
Next
X
X
X
L
H
X
X
H
L
L->H
Tri-State
WRITE Cycle (Begin Burst)
External
L
H
L
L
L
L
L
X
L
L->H
Data In (D)
WRITE Cycle (Continue Burst)
Next
X
X
X
L
H
X
L
X
L
L->H
Data In (D)
Notes:
2. X = “Don't Care.” H = Logic HIGH, L = Logic LOW. BWx = L signifies at least one Byte Write Select is active, BWx = Valid signifies that the desired Byte Write
Selects are asserted, see Truth Table for details.
3. Write is defined by BW
X
, and WE. See Truth Table for Read/Write.
4. When a Write cycle is detected, all I/Os are tri-stated, even during Byte Writes.
5. The DQs and DQP
X
pins are controlled by the current cycle and the OE signal. OE is asynchronous and is not sampled with the clock.
6. CEN = H, inserts wait states.
7. Device will power-up deselected and the I/Os in a tri-state condition, regardless of OE.
8. OE is asynchronous and is not sampled with the clock rise. It is masked internally during Write cycles. During a Read cycle DQs and DQP
X
= Tri-state when OE
is inactive or when the device is deselected, and DQs and DQP
X
= data when OE is active.
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