Cypress CY7C1350G manual Interleaved Burst Address Table MODE = Floating or VDD, Second

CY7C1350G

On the subsequent clock rise the data lines are automatically tri-stated regardless of the state of the OE input signal. This allows the external logic to present the data on DQs and DQP[A:D]. In addition, the address for the subsequent access (Read/Write/Deselect) is latched into the Address Register (provided the appropriate control signals are asserted).

On the next clock rise the data presented to DQs and DQP[A:D] (or a subset for Byte Write operations, see Write Cycle Description table for details) inputs is latched into the device and the write is complete.

The data written during the Write operation is controlled by BW[A:D] signals. The CY7C1350G provides byte write capability that is described in the Write Cycle Description table. Asserting the Write Enable input (WE) with the selected Byte Write Select (BW[A:D]) input will selectively write to only the desired bytes. Bytes not selected during a Byte Write operation will remain unaltered. A synchronous self-timed write 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 CY7C1350G 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:D] inputs. Doing so will tri-state the output drivers. As a safety precaution, DQs and DQP[A:D] are automatically tri-stated during the data portion of a write cycle, regardless of the state of OE.

Burst Write Accesses

The CY7C1350G 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

Truth Table[2, 3, 4, 5, 6, 7, 8]

ignored and the burst counter is incremented. The correct BW[A:D] 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	Second	Third	Fourth
	Address	Address	Address
A1, A0	A1, A0	A1, A0	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	Second	Third	Fourth
	Address	Address	Address
A1, A0	A1, A0	A1, A0	A1, A0
00	01	10	11
01	10	11	00
10	11	00	01
11	00	01	10

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	Tri-State
Continue Deselect Cycle	None	X	L	H	X	X	X	L	L-H	Tri-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	Tri-State
Dummy Read (Continue Burst)	Next	X	L	H	X	X	H	L	L-H	Tri-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)

Notes:

2.X =”Don't Care.” H = Logic HIGH, L = Logic LOW. CE stands for ALL Chip Enables active. BWx = L 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 BWX, and WE. See Write Cycle Descriptions table.

4.When a write cycle is detected, all DQs are tri-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 DQs 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[A:D] = tri-state when OE is inactive or when the device is deselected, and DQs and DQP[A:D] = data when OE is active.

Document #: 38-05524 Rev. *F Page 5 of 15

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