MBM29F400TC Fujitsu Media Devices, MBM29F400TC Datasheet - Page 12

• Manufacturer Part Number: MBM29F400TC
• Description: 4M (512K X 8/256K X 16) BIT
• Manufacturer: Fujitsu Media Devices

12
MBM29F400TC
Temporary Sector Unprotection
To activate this mode, the programming equipment must force V
V
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
with CE and OE at V
A
devices will produce 00H for unprotected sector. In this mode, the lower order addresses, except for A
A
A
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
A
4.2 for Autoselect codes.
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
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 V). During this mode, formerly protected sectors can be programmed or erased by selecting the sector
ID
1
6
-1
12
, A
are don't care. Address locations with A
) are the desired sector address will produce a logical “1” at DQ
requires to apply to V
= 11.5V), CE = V
0
) = (0, 1, 0) will produce a logical “1” code at device output DQ
IL
IL
, and A
and WE at V
IL
on byte mode.
6
-55/-70/-90
= V
IL
IH
. The sector addresses (A
. Scanning the sector addresses (A
1
= V
/MBM29F400BC
IL
are reserved for Autoselect manufacturer and device codes.
17
ID
, A
on address pin A
16
0
, A
for a protected sector. See Tables 4.1 and
0
for a protected sector. Otherwise the
15
, A
17
, A
14
, A
16
, A
13
, and A
15
-55/-70/-90
9
and control pin OE, (suggest
, A
14
, A
17
12
, A
) should be set to the
13
ID
, and A
16
, A
on address pin A
15
, A
12
14
) while (A
, A
0
, A
13
1
, and
, and
6
9
,