W29C020-90 Winbond Electronics, W29C020-90 Datasheet - Page 9

• Manufacturer Part Number: W29C020-90
• Manufacturer: Winbond Electronics

Specifications of W29C020-90

• Density: 2Mb
• Access Time (max): 90ns
• Interface Type: Parallel
• Boot Type: Bottom/Top
• Address Bus: 18b
• Operating Supply Voltage (typ): 5V
• Operating Temp Range: 0C to 70C
• Package Type: PDIP
• Program/erase Volt (typ): 5V
• Sync/async: Asynchronous
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Word Size: 8b
• Number Of Words: 256K
• Supply Current: 50mA
• Mounting: Through Hole
• Pin Count: 32
• Lead Free Status / Rohs Status: Supplier Unconfirmed

Command Codes for Boot Block Lockout Enable
Boot Block Lockout Enable Acquisition Flow
Notes for boot block lockout enable:
1. Data Format: DQ7 DQ0 (Hex)
2. Address Format: A14 A0 (Hex)
3. If you have any questions about this commend sequence, please contact the local distributor or Winbond Electronics Corp.
BYTE SEQUENCE
0 Write
1 Write
2 Write
3 Write
4 Write
5 Write
6 Write
BOOT BLOCK LOCKOUT FEATURE SET
ON FIRST 8K ADDRESS BOOT BLOCK
Boot Block Lockout
Feature Set on First 8K
Address Boot Block
ADDRESS
address 2AAA
address 00000
Load data AA
address 5555
address 5555
address 2AAA
Pause 10 mS
Load data 55
Load data 80
Load data AA
address 5555
address 5555
Load data 40
Load data 55
Load data 00
00000H
2AAAH
2AAAH
5555H
5555H
5555H
5555H
to
to
to
to
to
to
to
Pause 10 mS
- 9 -
DATA
Boot Block Lockout
Feature Set on Last 8K
Address Boot Block
AAH
AAH
55H
80H
55H
40H
00H
address 3FFFF
address 2AAA
Pause 10 mS
Load data AA
address 5555
address 2AAA
address 5555
address 5555
Load data AA
address 5555
Load data 40
Load data 80
Load data 55
Load data 55
Load data FF
to
to
to
to
to
to
to
Publication Release Date: February 1998
BOOT BLOCK LOCKOUT FEATURE SET
ON LAST 8K ADDRESS BOOT BLOCK
ADDRESS
3FFFFH
2AAAH
2AAAH
5555H
5555H
5555H
5555H
Pause 10 mS
W29C020
DATA
AAH
AAH
FFH
Revision A3
55H
80H
55H
40H