M29W128FH Datasheet, PDF (70/78 Pages) Numonyx B.V – 128 Mbit (8Mb x 16 or 16Mb x 8, Page, Uniform Block) 3V Supply Flash Memory

High Voltage Block Protection
M29W128FH, M29W128FL
D.2 In-System technique
The In-System technique requires a high voltage level on the Reset/Blocks Temporary Unprotect pin, RP
(1)_{. This can be achieved without violating the maximum ratings of the components on the}
microprocessor bus, therefore this technique is suitable for use after the memory has been fitted to the
system.
To protect a group of blocks follow the flowchart in Figure 20: In-System equipment Group Protect
flowchart. To unprotect the whole chip it is necessary to protect all of the groups first, then all the groups
can be unprotected at the same time. To unprotect the chip follow Figure 21: In-System equipment Chip
Unprotect flowchart.
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 allow the microprocessor to service interrupts that
will upset the timing and 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.
Note:
RP can be either at V_IH or at V_ID when using the In-System Technique to protect the
Extended Memory Block.
Table 36. Programmer technique Bus operations, 8-bit or 16-bit mode
Operation
EG
W
Address Inputs
A0-A22
Block (Group) Protect⁽¹⁾ V_IL
Chip Unprotect
V_ID
Block (Group) Protect
Verify
V_IL
Block (Group) Unprotect
Verify
V_IL
V_ID V_IL Pulse
A9 = V_ID, A12-A22 Block Address
Others = X
V_ID V_IL Pulse
V_IL
V_IH
A6 = V_IH, A9 = V_ID, A12 = V_IH,
A15 = V_IH Others = X
A0, A2, A3, A6 = V_IL, A1 = V_IH
A9 = V_ID, A12-A22= Block Address
Others = X
A0, A2, A3 = V_IL
V_IL
V_IH
A1, A6 = V_IH
A9 = V_ID, A12-A22 = Block Address
Others = X
1. Block Protection Groups are shown in Appendix D, Table 28.
Data Inputs/Outputs
DQ15A–1, DQ14-DQ0
X
X
Pass = xx01h
Retry = xx00h.
Pass = xx00h
Retry = xx01h.
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