m28w640fc Numonyx, m28w640fc Datasheet - Page 21
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m28w640fc
Manufacturer Part Number
m28w640fc
Description
64 Mbit 4mbx16, Boot Block 3v Supply Flash Memory
Manufacturer
Numonyx
Datasheet
1.M28W640FC.pdf
(77 pages)
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M28W640FCT, M28W640FCB
4.13
Block Lock command
The Block Lock command is used to lock a block and prevent Program or Erase operations
from changing the data in it. All blocks are locked at power-up or reset.
Two Bus Write cycles are required to issue the Block Lock command.
●
●
The lock status can be monitored for each block using the Read Electronic Signature
command.
The Block Lock bits are volatile, once set they remain set until a hardware reset or power-
down/power-up. They are cleared by a Blocks Unlock command. Refer to the section, Block
Locking, for a detailed explanation.
The first bus cycle sets up the Block Lock command.
The second Bus Write cycle latches the block address.
Table 10
shows the protection status after issuing a Block Lock command.
Command interface
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