MBM29F080A-55PF SPANSION [SPANSION], MBM29F080A-55PF Datasheet - Page 13

• Manufacturer Part Number: MBM29F080A-55PF
• Description: FLASH MEMORY CMOS 8M (1M x 8) BIT
• Manufacturer: SPANSION [SPANSION]

12
MBM29F080A
Write
Sector Group Protection
Temporary Sector Group Unprotection
The Autoselect mode also facilitates the determination of sector group protection in the system. By performing
a read operation at the address location XX02h with the higher order address bits A
desired sector group address, the device will return 01h for a protected sector group and 00h for a non-protected
sector group.
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 MBM29F080A 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 0-1, 2-3, 4-5, 6-7, 8-9, 10-11, 12-13, and 14-15 (see “Sector
Group Address Table” in “ FLEXIBLE SECTOR-ERASE ARCHITECTURE”). 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
“Sector Address Table” and “Sector Group Address Table” in “ FLEXIBLE SECTOR-ERASE ARCHITECTURE”
define the sector address for each of the thirty two (16) 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 “Temporary Sector Group Unprotection Timing Diagram” in “ TIMING DIAGRAM” and
“Temporary Sector Group Unprotection 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
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
“MBM29F080A Sector Protection Verify Autoselect Codes Table” in “ FLEXIBLE SECTOR-ERASE ARCHITEC-
TURE” for Autoselect codes.
This feature allows temporary unprotection of previously protected sector groups of the MBM29F080A device
in order to change data. The Sector Group Unprotection mode is activated by setting the RESET pin to high
voltage (12 V). During this mode, formerly protected sector groups can be programmed or erased by selecting
the sector group addresses. Once the 12 V is taken away from the RESET pin, all the previously protected sector
ID
17
) are the desired sector group address will produce a logical “1” at DQ
= 11.5 V), CE = V
IL
IL
. The sector addresses (A
and WE at V
1
= V
-55/-70/-90
IL
are reserved for Autoselect manufacturer and device codes.
IH
. Scanning the sector addresses (A
IL
19
, while CE is at V
, A
18
0
, and A
for a protected sector. Otherwise the device will produce
17
ID
) should be set to the sector to be protected.
on address pin A
IL
and OE is at V
19
0
, A
for a protected sector group. See
18
, and A
0
, A
9
1
IH
and control pin OE, (suggest
, and A
. Addresses are latched on
17
17
, A
) while (A
18
6
ID
are DON’T CARES.
and A
on address pin A
6
19
, A
19
set to the
, A
1
, A
18
0
, and
) = (0,
9