CY14V256LA

Document Number: 001-76295 Rev. *B

Page 6 of 22

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

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 re-enabled 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

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 written 0x00 in all cells.

Data Protection

The CY14V256LA protects data from corruption during low

voltage conditions by inhibiting all externally initiated STORE

and write operations. The low-voltage condition is detected when

and WE are LOW) at power up, after a RECALL or STORE, the

STORE takes place). This protects against inadvertent writes

L

H

L

0x0E38

0x31C7

0x03E0

0x3C1F

0x303F

0x0B46

Read SRAM

Read SRAM

Read SRAM

Read SRAM

Read SRAM

AutoStore

Enable

Output data

Output data

Output data

Output data

Output data

Output data

Active[3]

L

H

L

0x0E38

0x31C7

0x03E0

0x3C1F

0x303F

0x0FC0

Read SRAM

Read SRAM

Read SRAM

Read SRAM

Read SRAM

Nonvolatile

STORE

Output data

Output data

Output data

Output data

Output data

Output High Z

[3]

L

H

L

0x0E38

0x31C7

0x03E0

0x3C1F

0x303F

0x0C63

Read SRAM

Read SRAM

Read SRAM

Read SRAM

Read SRAM

Nonvolatile

RECALL

Output Data

Output Data

Output Data

Output Data

Output Data

Output High Z

Active[3]

Table 1. Mode Selection (continued)

CE

WE

OE

[1]

Mode

I/O

Power

Note

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