W49F020 Datasheet, PDF (8/21 Pages) Winbond – 256K X 8 CMOS FLASH MEMORY

Preliminary W49F020
Command Codes for Product Identification and Boot Block Lockout Detection
BYTE
SEQUENCE
ALTERNATE PRODUCT (6)
IDENTIFICATION/BOOT BLOCK
LOCKOUT DETECTION ENTRY
ADDRESS
DATA
SOFTWARE PRODUCT
IDENTIFICATION/BOOT BLOCK LOCKOUT
DETECTION EXIT (7)
ADDRESS
DATA
1 Write
5555
AA
5555H
AAH
2 Write
2AAA
55
2AAAH
55H
3 Write
5555
90
5555H
F0H
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 90
to
address 5555
Pause 10 µS
Product
Identification
and Boot Block
Lockout Detection
Mode (3)
Product
Identification Exit(7)
Load data AA
to
address 5555
(2)
Read address = 00000
data = DA
Load data 55
to
address 2AAA
(2)
Read address = 00001
data =8C
Load data F0
to
address 5555
(4)
Read address = 00002
data in DQ0 = "1"/"0"
Pause 10 µS
(5)
Normal Mode
Notes for software product identification/boot block lockout detection:
(1) Data Format: DQ7−DQ0 (Hex); Address Format: A14−A0 (Hex)
(2) A1−A17 = VIL; manufacture code is read for A0 = VIL; device code is read for A0 = VIH.
(3) The device does not remain in identification and boot block lockout detection mode if power down.
(4) If the output data in DQ0= " 1," the boot block programming lockout feature is activated; if the output data in DQ0= " 0," the lockout feature is
inactivated and the block can be programmed.
(5) The device returns to standard operation mode.
(6) Optional 1-word cycle (write F0 hex at XXXX address) can be used to exit the product identification/boot block lockout detection.
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