CY7C1352F
Document #: 38-05211 Rev. *C
Page 5 of 13
mechanism has been provided to simplify the write operations.
Byte write capability has been included in order to greatly
simplify Read/Modify/Write sequences, which can be reduced
to simple byte write operations.
Because the CY7C1352F is a common I/O device, data should
not be driven into the device while the outputs are active. The
Output Enable (OE) can be deasserted HIGH before
presenting data to the DQs and DQP[A:B] inputs. Doing so will
three-state the output drivers. As a safety precaution, DQs and
DQP[A:B] are automatically three-stated during the data portion
of a write cycle, regardless of the state of OE.
Burst Write Accesses
The CY7C1352F 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 subsequent clock
rise, the chip enables (CE1, CE2, and CE3) and WE inputs are
ignored and the burst counter is incremented. The correct
BW[A:B] 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. CE1, CE2, and CE3, 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
Truth Table [2, 3, 4, 5, 6, 7, 8]
Operation
Address
Used
CE
ZZ
ADV/LD
WE
BWx
OE
CEN
CLK
DQ
Deselect Cycle
None
H
L
L
X
X
X
L
L-H
three-state
Continue
Deselect Cycle
None
X
L
H
X
X
X
L
L-H
three-state
Read Cycle
(Begin Burst)
External
L
L
L
H
X
L
L
L-H
Data Out (Q)
Read Cycle
(Continue Burst)
Next
X
L
H
X
X
L
L
L-H
Data Out (Q)
NOP/Dummy Read
(Begin Burst)
External
L
L
L
H
X
H
L
L-H
three-state
Dummy Read
(Continue Burst)
Next
X
L
H
X
X
H
L
L-H
three-state
Write Cycle
(Begin Burst)
External
L
L
L
L
L
X
L
L-H
Data In (D)
Write Cycle
(Continue Burst)
Next
X
L
H
X
L
X
L
L-H
Data In (D)
NOP/WRITE ABORT
(Begin Burst)
None
L
L
L
L
H
X
L
L-H
three-state
Notes:
2. X=”Don't Care.” H= Logic HIGH, L =Logic LOW. CE stands for ALL Chip Enables active. BWX = 0 signifies at least one Byte Write Select is active, BWX = Valid
signifies that the desired byte write selects are asserted, see Write Cycle Description table for details.
3. Write is defined by BW[A:B], and WE. See Write Cycle Descriptions table.
4. When a write cycle is detected, all I/Os are three-stated, even during byte writes.
5. The DQ and DQP 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 three-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[A:B] = Three-state when
OE is inactive or when the device is deselected, and DQs and DQP[A:B] = data when OE is active.
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