MBM29DL324TD Fujitsu Media Devices, MBM29DL324TD Datasheet - Page 56

• Manufacturer Part Number: MBM29DL324TD
• Description: (MBM29DL32xBD) 32M (4M X 8/2M X 16) BIT Dual Operation
• Manufacturer: Fujitsu Media Devices

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56
MBM29DL32XTD/BD
• Write
Device erasure and programming are accomplished via the command register. The contents of the register serve
as inputs to the internal state machine. The state machine outputs dictate the function of the device.
The command register itself does not occupy any addressable memory location. The register is a latch used to
store the commands, along with the address and data information needed to execute the command. The
command register is written by bringing WE to V
the falling edge of WE or CE, whichever happens later; while data is latched on the rising edge of WE or CE,
whichever happens first. Standard microprocessor write timings are used.
Refer to AC Write Characteristics and the Erase/Programming Waveforms for specific timing parameters.
• Sector Group Protection
The MBM29DL32XTD/BD feature hardware sector group protection. This feature will disable both program and
erase operations in any combination of twenty five sector groups of memory. (See Tables 9.1 and 9.2). The
sector group protection feature is enabled using programming equipment at the user’s site. The device is shipped
with all sector groups unprotected.
To activate this mode, the programming equipment must force V
V
A
the seventy one (71) individual sectors, and tables 9.1 and 9.2 define the sector group address for each of the
twenty five (25) individual group 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 group addresses must be held constant
during the WE pulse. See Figures 18 and 26 for sector group protection waveforms and algorithm.
To verify programming of the protection circuitry, the programming equipment must force V
with CE and OE at V
and A
Otherwise the device will produce “0” for unprotected sector. In this mode, the lower order addresses, except
for A
and device codes. A
It is also possible to determine if a sector group 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
sector group. See Tables 11.1 to 11.8 for Autoselect codes.
• Temporary Sector Group Unprotection
This feature allows temporary unprotection of previously protected sector groups of the MBM29DL32XTD/BD
devices in order to change data. The Sector Group Unprotection mode is activated by setting the RESET pin to
high voltage (V
the sector group addresses. Once the V
groups will be protected again. Refer to Figures 19 and 27.
ID
13
17
, and A
, A
= 11.5 V), CE = V
0
, A
16
12
, A
) while (A
1
, and A
15
12
, A
) should be set to the sector to be protected. Tables 5.1 to 8.2 define the sector address for each of
14
ID
, A
6
). During this mode, formerly protected sector groups can be programmed or erased by selecting
6
are DON’T CARES. Address locations with A
, A
13
, and A
1
-1
IL
, A
IL
requires to apply to V
and WE at V
and A
0
) = (0, 1, 0) will produce a logical “1” code at device output DQ
12
) are the desired sector group address will produce a logical “1” at DQ
0
= A
6
IH
= V
. Scanning the sector group addresses (A
IL
ID
, A
-80/90/12
is taken away from the RESET pin, all the previously protected sector
1
IL
= V
on byte mode.
IH
IL
, while CE is at V
. The sector group addresses (A
ID
1
= V
on address pin A
IL
IL
and OE is at V
are reserved for Autoselect manufacturer
20
, A
9
20
IH
and control pin OE, (suggest
19
, A
. Addresses are latched on
, A
19
18
0
, A
, A
for a protected sector.
18
ID
17
, A
on address pin A
, A
17
0
16
, A
for a protected
, A
20
16
15
, A
, A
, A
19
15
14
, A
, A
, A
18
14
13
,
,
9
,