CY14B256L-ZS25XI Ver la hoja de datos (PDF) - Cypress Semiconductor

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Fabricante

CY14B256L-ZS25XI

256-Kbit (32 K × 8) nvSRAM

Cypress Semiconductor 

CY14B256LA

Table 1. Mode Selection (continued)

CE

WE

OE

A14–A0[6]

Mode

I/O

Power

L

H

L

0x0E38

Read SRAM

Output data

Active[8]

0x31C7

Read SRAM

Output data

0x03E0

Read SRAM

Output data

0x3C1F

Read SRAM

Output data

0x303F

Read SRAM

Output data

0x0B46

AutoStore Enable Output data

L

H

L

0x0E38

Read SRAM

Output data

Active ICC2[8]

0x31C7

Read SRAM

Output data

0x03E0

Read SRAM

Output data

0x3C1F

Read SRAM

Output data

0x303F

Read SRAM

Output data

0x0FC0

Nonvolatile

Output high Z

STORE

L

H

L

0x0E38

Read SRAM

Output data

Active[8]

0x31C7

Read SRAM

Output data

0x03E0

Read SRAM

Output data

0x3C1F

Read SRAM

Output data

0x303F

Read SRAM

Output data

0x0C63

Nonvolatile

Output high Z

Recall

Preventing AutoStore

The AutoStore function is disabled by initiating an AutoStore

disable sequence. A sequence of read operations is performed

in a manner similar to the Software STORE initiation. To initiate

the AutoStore disable sequence, the following sequence of CE

or OE controlled read operations must be performed:

1. Read address 0x0E38 valid READ

2. Read address 0x31C7 valid READ

3. Read address 0x03E0 valid READ

4. Read address 0x3C1F valid READ

5. Read address 0x303F valid READ

6. Read address 0x0B45 AutoStore disable

The AutoStore is reenabled by initiating an AutoStore enable

sequence. A sequence of read operations is performed in a

manner similar to the Software RECALL initiation. To initiate the

AutoStore enable sequence, the following sequence of CE or OE

controlled read operations must be performed:

1. Read address 0x0E38 valid READ

2. Read address 0x31C7 valid READ

3. Read address 0x03E0 valid READ

4. Read address 0x3C1F valid READ

5. Read address 0x303F valid READ

6. Read address 0x0B46 AutoStore enable

If the AutoStore function is disabled or reenabled, a manual

STORE operation (Hardware or Software) must be issued to

save the AutoStore state through subsequent power-down

cycles. The part comes from the factory with AutoStore enabled

and 0x00 written in all cells.

Data Protection

The CY14B256LA protects data from corruption during low

voltage conditions by inhibiting all externally initiated STORE

and write operations. The low voltage condition is detected when

VCC is less than VSWITCH. If the CY14B256LA is in a write mode

(both CE and WE are LOW) at power-up, after a RECALL or

STORE, the write is inhibited until the SRAM is enabled after

tLZHSB (HSB to output active). This protects against inadvertent

writes during power-up or brown out conditions.

Note

8. The six consecutive address locations must be in the order listed. WE must be HIGH during all six cycles to enable a nonvolatile cycle.

Document Number: 001-54707 Rev. *I

Page 7 of 22

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