M29F800FB55N3E2 Datasheet, PDF (32/55 Pages) Micron Technology – Micron Parallel NOR Flash Embedded Memory

M29FxxxFT/B
Block Protection Operations
Table 7: Block and Chip Protection Signal Settings (Continued)
Signals
DQ[15]/A-1, and
DQ[14:0]
Block Protect
X
X
Chip Unprotect
X
X
Verify Block Protec-
tion
Pass = XX01h
Retry = XX00h
Verify Block Unpro-
tect
Retry = XX01h
Pass = XX00h
Note: 1. H = Logic level HIGH (V_IH); L = Logic level LOW (V_IL); X = HIGH or LOW.
Programmer Technique
The Programmer technique uses high (V_ID) voltage levels on some of the bus pins.
These cannot be achieved using a standard microprocessor bus, therefore the techni-
que is recommended only for use in Programming Equipment.
To protect a block, follow the Programmer Equipment Block Protect flowchart. During
the Block Protect algorithm, the A19-A12 Address Inputs indicate the address of the
block to be protected. The block will be correctly protected only if A19-A12 remain valid
and stable, and if Chip Enable is kept Low, V_IL, all along the Protect and Verify phases.
The Chip Unprotect algorithm is used to unprotect all the memory blocks at the same
time. This algorithm can only be used if all of the blocks are protected first. To unprotect
the chip follow the Programmer Equipment Chip Unprotect flowchart and the Program-
mer Technique Block Protection table, which give a summary of each operation.
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 be-
fore reaching the end. Chip Unprotect can take several seconds and a user message
should be provided to show that the operation is progressing.
Figure 17: Block Protect Flowchart – Programmer Equipment
Setup
START
ADDRESS = BLOCK ADDRESS
WE# = VIH
n=0
Protect
OE#, A9 = VID ,
CE# = VIL
Wait 4µs
WE# = VIL
Wait 100µs
WE# = VIH
Verify
CE#, OE# =,VIH
A0, A6 = VIL ,
A1 = VIH
CE# = VIL
Wait 4µs
OE# = VIL
Wait 60ns
Read DATA
End
DATA
No
=
01h
Yes
A9 = VIH
CE#, OE# = VIH
PASS
++n
No
= 25
Yes
A9 = VIH
CE#, OE# = VIH
FAIL
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m29fxxxf/t_2mb-16mb.pdf - Rev. B 2/14 EN
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