MBM29LV160T Fujitsu Media Devices, MBM29LV160T Datasheet - Page 16

• Manufacturer Part Number: MBM29LV160T
• Description: 16M (2M x 8/1M x 16) BIT
• Manufacturer: Fujitsu Media Devices

16
MBM29LV160T
Write
Sector Protection
Temporary Sector Unprotection
Device erasure and programming are accomplished via the command register. The command register is written
by bringing WE to V
WE, whichever occurs later, while data is latched on the rising edge of CE or WE pulse, whichever occurs first.
Standard microprocessor write timings are used. See Figures 6 to 8.
Refer to AC Write Characteristics and the Erase/Programming Waveforms for specific timing parameters.
The MBM29LV160T/B features hardware sector protection. This feature will disable both program and erase
operations in any number of sectors (0 through 34). The sector protection feature is enabled using programming
equipment at the user’s site. The device is shipped with all sectors unprotected.
To activate this mode, the programming equipment must force V
V
the sector to be protected. Tables 5 and 6 define the sector address for each of the thirty five (35) 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 24 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
while (A
device will read 00H for an unprotected sector. In this mode, the lower order addresses, except for A
A
codes. 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 pins (A
A
Tables 4.1 and 4.2 for Autoselect codes.
This feature allows temporary unprotection of previously protected sectors of the MBM29LV160T/B devices 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.
(See Figures 18 and 25.)
IL
6
14
, A
are DON’T CARES. Address locations with A
, A
0
13
= A
, and A
6
, A
-1
6
requires to V
1
= V
, A
12
0
IL
) = (0, 1, 0) will produce a logical “1” at device output DQ
) represents the sector address will produce a logical “1” at DQ
, A
1
IL
= V
IL
, while CE is at V
and WE at V
IH
IL
. The sector addresses pins (A
in byte mode.
-80/-90/-12
IH
. Scanning the sector addresses (A
IL
and OE is at V
/MBM29LV160B
1
= V
IL
IH
are reserved for Autoselect manufacturer and device
. Addresses are latched on the falling edge of CE or
19
, A
18
, A
ID
17
on address pin A
, A
16
, A
19
0
15
for a protected sector. Otherwise the
, A
, A
18
14
, A
, A
0
for a protected sector. See
17
13
-80/-90/-12
, A
9
, and A
and control pin OE, CE =
16
, A
15
ID
19
12
, A
on address pin A
) should be set to
, A
14
18
, A
, A
13
17
, and A
0
, A
, A
16
1
, and
, A
12
15
)
9
,