m29dw128f-70za6t Numonyx, m29dw128f-70za6t Datasheet - Page 85

• Manufacturer Part Number: m29dw128f-70za6t
• Description: 128 Mbit 16mb X8 Or 8mb X16, Multiple Bank, Page, Boot Block 3v Supply Flash Memory
• Manufacturer: Numonyx

M29DW128F
Appendix D
D.1
The High Voltage Block Protection can be used to prevent any operation from modifying the
data stored in the memory. The blocks are protected in groups, refer to
for details of the Protection Groups. Once protected, Program and Erase operations within
the protected group fail to change the data.
There are three techniques that can be used to control Block Protection, these are the
Programmer technique, the In-System technique and Temporary Unprotection. Temporary
Unprotection is controlled by the Reset/Block Temporary Unprotection pin, RP; this is
described in the Signal Descriptions section.
To protect the Extended Block issue the Enter Extended Block command and then use
either the Programmer or In-System technique. Once protected issue the Exit Extended
Block command to return to read mode. The Extended Block protection is irreversible, once
protected the protection cannot be undone.
Programmer technique
The Programmer technique uses high (V
cannot be achieved using a standard microprocessor bus, therefore the technique is
recommended only for use in Programming Equipment.
To protect a group of blocks follow the flowchart in
Protect flowchart
then all groups can be unprotected at the same time. To unprotect the chip follow
Programmer equipment Chip Unprotect flowchart
operations, 8-bit or 16-bit mode
The timing on these flowcharts is critical. Care should be taken to ensure that, where a
pause is specified, it is followed as closely as possible. Do not abort the procedure before
reaching the end. Chip Unprotect can take several seconds and a user message should be
provided to show that the operation is progressing.
High Voltage Block Protection
. To unprotect the whole chip it is necessary to protect all of the groups first,
, gives a summary of each operation.
ID
) voltage levels on some of the bus pins. These
.
Figure 23: Programmer equipment Group
Table 42: Programmer technique Bus
High Voltage Block Protection
Appendix A
Figure 24:
,
Table 34
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