MBM29F400TC
-55/-70/-90
/MBM29F400BC
-55/-70/-90
To activate this mode, the programming equipment must force V
ID
on address pin A
9
and control pin OE, (suggest
V
ID
= 11.5V), CE = V
IL
, and A
6
= V
IL
. The sector addresses (A
17
, A
16
, A
15
, A
14
, A
13
, and A
12
) should be set to the
sector to be protected. Tables 5 and 6 define the sector address for each of the eleven (11) 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. Refer to Figures 16 and
23 for sector protection waveforms and algorithm.
To verify programming of the protection circuitry, the programming equipment must force V
ID
on address pin A
9
with CE and OE at V
IL
and WE at V
IH
. Scanning the sector addresses (A
17
, A
16
, A
15
, A
14
, A
13
, and A
12
) while (A
6
,
A
1
, A
0
) = (0, 1, 0) will produce a logical “1” code at device output DQ
0
for a protected sector. Otherwise the
devices will produce 00H for unprotected sector. In this mode, the lower order addresses, except for A
0
, A
1
, and
A
6
are don't care. Address locations with A
1
= V
IL
are reserved for Autoselect manufacturer and device codes.
A
-1
requires to apply to V
IL
on byte mode.
It is also possible to determine if a sector is protected in the system by writing an Autoselect command. Performing
a read operation at the address location XX02H, where the higher order addresses (A
17
, A
16
, A
15
, A
14
, A
13
, and
A
12
) are the desired sector address will produce a logical “1” at DQ
0
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 MBM29F400TC/BC device in
order to change data. The Sector Unprotection mode is activated by setting the RESET pin to high voltage
(12 V). During this mode, formerly protected sectors can be programmed or erased by selecting the sector
addresses. 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.
12
FUJITSU [ FUJITSU COMPONENT LIMITED. ]
