MBM29F400BC-55PF SPANSION [SPANSION], MBM29F400BC-55PF Datasheet - Page 14

• Manufacturer Part Number: MBM29F400BC-55PF
• Description: FLASH MEMORY CMOS 4M (512K x 8/256K x 16) BIT
• Manufacturer: SPANSION [SPANSION]

Write
Sector Protection
Temporary Sector Unprotection
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 MBM29F400TC/BC features hardware sector protection. This feature will disable both program and erase
operations in any number of sectors (0 through 10). 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
sector to be protected. “Sector Address Table (MBM29F400TC)” and “Sector Address Table (MBM29F400BC)”
in FLEXIBLE SECTOR ERASE ARCHITECTURE 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 “AC Waveforms for Sector Protection Timing Diagram” in TIMING DIAGRAM and “Sector Protection
Algorithm” in FLOW CHART 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
BC Sector Protection Verify Autoselect Codes” and “Expanded Autoselect Code Table” in DEVICE BUS
OPERATION 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 “Temporary Sector Unprotection Timing Diagram” in TIMING DIAGRAM and “Temporary Sector
Unprotection Algorithm” in FLOW CHART.
(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
MBM29F400TC
= 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
= V
IL
IH
. The sector addresses (A
. Scanning the sector addresses (A
-55/-70-90
1
= V
IL
IL
, while CE is at V
are reserved for Autoselect manufacturer and device codes.
/MBM29F400BC
17
ID
, A
on address pin A
0
16
IL
for a protected sector. See “MBM29F400TC/
, A
and OE is at V
0
for a protected sector. Otherwise the
15
, A
17
, A
14
, A
16
, A
13
, and A
15
9
IH
and control pin OE, (suggest
, A
. Addresses are latched on
14
17
, A
12
, A
) should be set to the
13
ID
16
, and A
, A
on address pin A
-55/-70-90
15
, A
12
14
) while (A
, A
0
, A
13
1
, and
, and
6
9
,
13