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Preventing autostore – Cypress CY14B108M User Manual

Page 5

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PRELIMINARY

CY14B108K, CY14B108M

Document #: 001-47378 Rev. **

Page 5 of 29

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 0x4E38 Valid READ

2. Read address 0xB1C7 Valid READ

3. Read address 0x83E0 Valid READ

4. Read address 0x7C1F Valid READ

5. Read address 0x703F Valid READ

6. Read address 0x8B45 AutoStore Disable

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 or OE
controlled read operations must be performed:

1. Read address 0x4E38 Valid READ

2. Read address 0xB1C7 Valid READ

3. Read address 0x83E0 Valid READ

4. Read address 0x7C1F Valid READ

5. Read address 0x703F Valid READ

6. Read address 0x4B46 AutoStore Enable

If the AutoStore function is disabled or re-enabled, a manual
STORE operation (hardware or software) issued to save the
AutoStore state through subsequent power down cycles. The
part comes from the factory with AutoStore enabled.

Table 2. Mode Selection

CE

WE

OE, BHE, BLE

[3]

A

15

- A

0

[5]

Mode

I/O

Power

H

X

X

X

Not Selected

Output High Z

Standby

L

H

L

X

Read SRAM

Output Data

Active

L

L

X

X

Write SRAM

Input Data

Active

L

H

L

0x4E38

0xB1C7

0x83E0

0x7C1F

0x703F

0x8B45

Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM

AutoStore

Disable

Output Data
Output Data
Output Data
Output Data
Output Data
Output Data

Active

[6]

L

H

L

0x4E38

0xB1C7

0x83E0

0x7C1F

0x703F

0x4B46

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

[6]

L

H

L

0x4E38

0xB1C7

0x83E0

0x7C1F

0x703F

0x8FC0

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

Active I

CC2

[6]

L

H

L

0x4E38

0xB1C7

0x83E0

0x7C1F

0x703F

0x4C63

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

[6]

Notes

5. While there are 20 address lines on the CY14B108K (19 address lines on the CY14B108M), only the 13 address lines (A

14

- A

2

) are used to control software modes.

The remaining address lines are don’t care.

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

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