M29DW641F70N1 NUMONYX [Numonyx B.V], M29DW641F70N1 Datasheet - Page 33

• Manufacturer Part Number: M29DW641F70N1
• Description: 64 Mbit (4Mb x16, Multiple Bank, Page, Boot Block) 3V Supply Flash Memory
• Manufacturer: NUMONYX [Numonyx B.V]

M29DW641F
6.3
6.3.1
6.3.2
6.3.3
Block Protection commands
Blocks or groups of blocks can be protected against accidental program, Erase or Read
Operations. The Protection Groups are shown in
The device block protection scheme is shown in
Figure 5: Block Protection state diagram
summary of the Block Protection commands.
Only the commands related to the Extended Block Protection are available in both 8 bit and
16 bit memory configuration. The other block protection commands are available in 16-bit
configuration only.
Enter Extended Block command
The M29DW641F has one extra 128-Word block (Extended Block) that can only be
accessed using the Enter Extended Block command.
Three Bus Write cycles are required to issue the Extended Block command. Once the
command has been issued the device enters Extended Block mode where all Bus Read or
Program Operations to the Extended Block Addresses (see
The Extended Block cannot be erased, and can be treated as one-time programmable
(OTP) memory. In Extended Block mode only array cell locations (Bank A) with the same
addresses as the Extended Block are not accessible. In Extended Block mode Dual
Operations are allowed and the Extended Block physically belongs to Bank A.
In Extended Block mode, Erase, Chip Erase, Erase Suspend and Erase resume commands
are not allowed.
To exit from the Extended Block mode the Exit Extended Block command must be issued.
The Extended Block can be protected by setting the Extended Block Protection bit to ‘1’;
however once protected the protection cannot be undone.
Exit Extended Block command
The Exit Extended Block command is used to exit from the Extended Block mode and return
the device to Read mode. Four Bus Write Operations are required to issue the command.
Set Extended Block Protection bit command
The Set Extended Block Protection bit command programs the Extended Block Protection
bit to ‘1’ thus preventing the second section of the Extended Block from being programmed.
A Read/Reset command must be issued to abort a Set Extended Block Protection bit
command.
Six successive steps are required to issue the Set Extended Block Protection bit command.
1.
2.
3.
The command starts with two unlock cycles.
The third Bus Write cycle sets up the Set Extended Block Protection bit command.
The last three cycles verify the value programmed at the Extended Block Protection bit
address: if bit DQ0 of Data Inputs/Outputs is set to ’1’, it indicates that the Extended
Block Protection bit has been successfully programmed. If DQ0 is ‘0’, the Set Extended
Block Protection bit command must be issued and verified again.
. See
Table 10: Block Protection commands
Figure 6: Software Protection scheme
Appendix A
Table 28: Block Addresses
,
Table 28: Block Addresses
Command interface
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