MBM29F800TA-55/-70/-90/MBM29F800BA-55/-70/-90
To activate this mode, the programming equipment must force VID on address pin A9 and control pin OE, (suggest
VID = 11.5V), CE = VIL, and A6 = VIL. The sector addresses (A18, A17, A16, A15, A14, A13, and A12) should be set to
the sector to be protected. Tables 5 and 6 define the sector address for each of the nineteen (19) individual
sectors. Programming of the protection circuitry begins on the falling edge of the WE pulse and is terminated
with the rising edge of the same. Sector addresses must be held constant during the WE pulse. See Figures 16
and 23 for sector protection waveforms and algorithm.
To verify programming of the protection circuitry, the programming equipment must force VID on address pin A9
with CE and OE at VIL and WE at VIH. Scanning the sector addresses (A18, A17, A16, A15, A14, A13, and A12) while
(A6, A1, A0) = (0, 1, 0) will produce a logical “1” code at device output DQ0 for a protected sector. Otherwise the
devices will read 00H for unprotected sector. In this mode, the lower order addresses, except for A0, A1, and A6
are DON’T CARES. Address locations with A1 = VIL are reserved for Autoselect manufacturer and device codes.
A-1 requires to apply to VIL on byte mode.
ItisalsopossibletodetermineifasectorisprotectedinthesystembywritinganAutoselectcommand. Performing
a read operation at the address location XX02H, where the higher order addresses (A18, A17, A16, A15, A14, A13,
and A12) are the desired sector address will produce a logical “1” at DQ0 for a protected sector. See Tables 4.1
and 4.2 for Autoselect codes.
Temporary Sector Unprotection
This feature allows temporary unprotection of previously protected sectors of the MBM29F800TA/BA device in
order to change data. The Sector Unprotection mode is activated by setting the RESET pin to high voltage (12
V). Duringthismode, formerlyprotectedsectorscanbeprogrammedorerasedbyselectingthesectoraddresses.
Once the 12 V is taken away from the RESET pin, all the previously protected sectors will be protected again.
Refer to Figures 17 and 24.
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