MBM29F016A-12 FUJITSU [Fujitsu Component Limited.], MBM29F016A-12 Datasheet - Page 11

• Manufacturer Part Number: MBM29F016A-12
• Description: 16M (2M X 8) BIT
• Manufacturer: FUJITSU [Fujitsu Component Limited.]

Write
Sector Group Protection
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.
The MBM29F016A features hardware sector group protection. This feature will disable both program and erase
operations in any combination of eight sector groups of memory. Each sector group consists of four adjacent
sectors grouped in the following pattern: sectors 0-3, 4-7, 8-11, 12-15, 16-19, 20-23, 24-27, and 28-31 (see
Table 5). 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
Tables 4 and 5 define the sector address for each of the thirty two (32) individual sectors, and the sector group
address for each of the eight (8) 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 addresses must be held
constant during the WE pulse. See figures 14 and 21 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
1, 0) will produce a logical “1” code at device output DQ
00H for unprotected sector. In this mode, the lower order addresses, except for A
Address locations with 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
Table 3 for Autoselect codes.
ID
18
) are the desired sector group address will produce a logical “1” at DQ
= 11.5 V), CE = V
SGA0
SGA1
SGA2
SGA3
SGA4
SGA5
SGA6
SGA7
IL
IL
. The sector addresses (A
and WE at V
1
= V
A
0
0
0
0
1
1
1
1
20
IL
are reserved for Autoselect manufacturer and device codes.
Table 5
IH
. Scanning the sector addresses (A
Sector Group Addresses
IL
20
A
, while CE is at V
0
0
1
1
0
0
1
1
, A
19
19
0
, and A
for a protected sector. Otherwise the device will produce
18
ID
) should be set to the sector to be protected.
MBM29F016A
on address pin A
IL
and OE is at V
A
0
1
0
1
0
1
0
1
18
20
0
, A
for a protected sector group. See
19
, and A
0
, A
9
1
IH
and control pin OE, (suggest
, and A
. Addresses are latched on
18
) while (A
SA12 to SA15
SA16 to SA19
SA20 to SA23
SA24 to SA27
SA28 to SA31
SA8 to SA11
6
SA0 to SA3
SA4 to SA7
ID
are DON’T CARES.
Sectors
on address pin A
-70/-90/-12
6
, A
20
, A
1
, A
19
0
, and
) = (0,
9
11