W29C020

- 8 -

Command Codes for Product Identification and Boot Block Lockout Detection

BYTE

SEQUENCE

ALTERNATE PRODUCT (7)

IDENTIFICATION/BOOT BLOCK

LOCKOUT DETECTION ENTRY

SOFTWARE PRODUCT

IDENTIFICATION/BOOT BLOCK

LOCKOUT DETECTION ENTRY

SOFTWARE PRODUCT

IDENTIFICATION/BOOT BLOCK

LOCKOUT DETECTION EXIT

ADDRESS

DATA

ADDRESS

DATA

ADDRESS

DATA

0 Write

5555

AA

5555H

AAH

5555H

AAH

1 Write

2AAA

55

2AAAH

55H

2AAAH

55H

2 Write

5555

90

5555H

80H

5555H

F0H

3 Write

-

-

5555H

AAH

-

-

4 Write

-

-

2AAAH

55H

-

-

5 Write

-

-

5555H

60H

-

-

Pause 10

µS

Pause 10

µS

Pause 10

µS

Software Product Identification and Boot Block Lockout Detection Acquisition Flow

Product

Identification

Entry (1)

Load data AA

to

address 5555

Load data 55

to

address 2AAA

Load data 80

to

address 5555

Load data AA

to

address 5555

Load data 55

to

address 2AAA

Load data 60

to

address 5555

Product

Identification

and Boot Block

Lockout Detection

Mode (3)

Read address = 00000

data = DA

Read address = 00001

data = 45

Read address = 00002

data = FF/FE

(4)

Read address = 3FFF2

data = FF/FE

(5)

Product

Identification

Exit (1)

Load data AA

to

address 5555

Load data 55

to

address 2AAA

Load data F0

to

address 5555

Pause 10 S

Normal Mode

(6)

(2)

(2)

Pause 10 S

µ

µ

Notes for software product identification/boot block lockout detection:

(1) Data Format: DQ7

−DQ0 (Hex); Address Format: A14−A0 (Hex)

(2) A1

(3) The device does not remain in identification and boot block (address 0002 Hex/3FFF2 Hex respond to first 8K/last 8K) lockout detection mode if

power down.

(4), (5) If the output data is "FF Hex," the boot block programming lockout feature is activated; if the output data "FE Hex," the lockout feature is

inactivated and the block can be programmed.

(6) The device returns to standard operation mode.

(7) This product supports both the JEDEC standard 3 byte command code sequence and original 6 byte command code sequence. For new

designs, Winbond recommends that the 3 byte command code sequence be used.