M29W400DT_07 Datasheet, PDF (46/48 Pages) STMicroelectronics – 4 Mbit (512 Kb x 8 or 256 Kb x 16, boot block) 3 V supply Flash memory

Block protection
M29W400DT, M29W400DB
Figure 22. In-system equipment chip unprotect flowchart
START
PROTECT ALL BLOCKS
n=0
CURRENT BLOCK = 0
RP = VID
WRITE 60h
ANY ADDRESS WITH
A0 = VIL, A1 = VIH, A6 = VIH
WRITE 60h
ANY ADDRESS WITH
A0 = VIL, A1 = VIH, A6 = VIH
Wait 10 ms
WRITE 40h
ADDRESS = CURRENT BLOCK ADDRESS
A0 = VIL, A1 = VIH, A6 = VIH
Wait 4 µs
READ DATA
ADDRESS = CURRENT BLOCK ADDRESS
A0 = VIL, A1 = VIH, A6 = VIH
INCREMENT
CURRENT BLOCK
NO ⁺⁺ⁿ
= 1000
YES
RP = VIH
ISSUE READ/RESET
COMMAND
FAIL
NO DATA YES
=
00h
LAST NO
BLOCK
YES
RP = VIH
ISSUE READ/RESET
COMMAND
PASS
AI03472
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