w29c020-12b Winbond Electronics Corp America, w29c020-12b Datasheet - Page 8

• Manufacturer Part Number: w29c020-12b
• Description: 256k X 8 Cmos Flash Memory
• Manufacturer: Winbond Electronics Corp America

Command Codes for Product Identification and Boot Block Lockout Detection
Software Product Identification and Boot Block Lockout Detection Acquisition Flow
Notes for software product identification/boot block lockout detection:
(1) Data Format: DQ7 DQ0 (Hex); Address Format: A14 A0 (Hex)
(2) A1 A16 = V
(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
(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
(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
SEQUENCE
power down.
inactivated and the block can be programmed.
designs, Winbond recommends that the 3 byte command code sequence be used.
1 Write
2 Write
3 Write
4 Write
5 Write
0 Write
BYTE
IL
; manufacture code is read for A0 = V
IDENTIFICATION/BOOT BLOCK
LOCKOUT DETECTION ENTRY
ADDRESS
ALTERNATE PRODUCT (7)
2AAA
5555
5555
-
-
-
Pause 10 S
Product
Identification
Entry (1)
address 2AAA
address 2AAA
address 5555
Load data AA
address 5555
address 5555
Load data 55
address 5555
Load data AA
Load data 55
Load data 60
Pause 10 S
Load data 80
to
to
to
to
to
to
DATA
AA
55
90
-
-
-
IL
; device code is read for A0 = V
Product
Identification
and Boot Block
Lockout Detection
Mode (3)
Read address = 00001
Read address = 00000
Read address = 00002
Read address = 3FFF2
IDENTIFICATION/BOOT BLOCK
LOCKOUT DETECTION ENTRY
data = FF/FE
data = FF/FE
ADDRESS
data = DA
data = 45
2AAAH
2AAAH
5555H
5555H
5555H
5555H
SOFTWARE PRODUCT
- 8 -
Pause 10 S
(4)
(5)
(2)
(2)
IH
.
DATA
AAH
AAH
55H
80H
55H
60H
Product
Identification
Exit (1)
Load data AA
Normal Mode
address 2AAA
address 5555
address 5555
Load data F0
Load data 55
Pause 10 S
to
to
to
IDENTIFICATION/BOOT BLOCK
LOCKOUT DETECTION EXIT
ADDRESS
2AAAH
5555H
5555H
SOFTWARE PRODUCT
-
-
-
Pause 10 S
(6)
W29C020
DATA
AAH
55H
F0H
-
-
-