M28W640 STMicroelectronics, M28W640 Datasheet - Page 18

• Manufacturer Part Number: M28W640
• Description: 64 Mbit 4Mb x16/ Boot Block 3V Supply Flash Memory
• Manufacturer: STMicroelectronics

M28W640CT, M28W640CB
Table 9. Protection Status
Note: 1. The lock status is defined by the write protect pin and by DQ1 (‘1’ for a locked-down block) and DQ0 (‘1’ for a locked block) as read
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Current State
2. All blocks are locked at power-up, so the default configuration is 001 or 101 according to WP status.
3. A WP transition to V
1,0,1
0,0,1
1,0,0
1,1,0
1,1,1
0,0,0
0,1,1
in the Read Electronic Signature command with A1 = V
Protection Status
(2)
(2)
(WP, DQ1, DQ0)
Current
Program/Erase
Allowed
IH
on a locked block will restore the previous DQ0 value, giving a 111 or 110.
(1)
yes
yes
yes
no
no
no
no
Block Lock
Command
After
1,0,1
1,0,1
1,1,1
1,1,1
0,0,1
0,0,1
0,1,1
IH
and A0 = V
Block Unlock
Command
Next Protection Status
After
1,0,0
1,0,0
1,1,0
1,1,0
0,0,0
0,0,0
0,1,1
IL
.
(WP, DQ1, DQ0)
After Block
Lock-Down
Command
1,1,1
1,1,1
1,1,1
1,1,1
0,1,1
0,1,1
0,1,1
(1)
1,1,1 or 1,1,0
WP transition
After
0,0,0
0,0,1
0,1,1
0,1,1
1,0,0
1,0,1
(3)