15
MBM29F033C
-70/-90/-12
Temporary Sector Group Unprotection
This feature allows temporary unprotection of previously protected sector groups of the MBM29F033C 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
groups will be protected again. Refer to Figures 13 and 20.
Notes:
1. Address bits A
18
to
A
21
= X = “H” or “L” for all address commands except or Program Address (PA) and
Sector Address (SA).
2. Bus operations are defined in Table 2.
3. RA = Address of the memory location to be read.
PA = Address of the memory location to be programmed. Addresses are latched on the falling edge
of the WE pulse.
SA = Address of the sector to be erased. The combination of A
21
, A
20
, A
19
, A
18
, A
17
, and A
16
will uniquely
select any sector.
4. RD = Data read from location RA during read operation.
PD = Data to be programmed at location PA. Data is latched on the rising edge of WE.
5. Read and Byte program functions to non-erasing sectors are allowed in the Erase Suspend mode.
6. X = “H” or “L”
* :Either of the two reset commands will reset the device.
Command Definitions
Device operations are selected by writing specific address and data sequences into the command register.
Writing incorrect address and data values or writing them in the improper sequence will reset the device to the
read mode. Table 6 defines the valid register command sequences. Note that the Erase Suspend (B0H) and
Erase Resume (30H) commands are valid only while the Sector Erase operation is in progress. Moreover, both
Read/Reset commands are functionally equivalent, resetting the device to the read mode.
Table 6 MBM29F033C Command Definitions
Command
Sequence
Bus
Write
Cycle
s
Req'd
First Bus
Write Cycle
Second Bus
Write Cycle
Third Bus
Write Cycle
Fourth Bus
Read/Write
Cycle
Fifth Bus
Write Cycle
Sixth Bus
Write Cycle
Addr. Data Addr. Data Addr. Data Addr. Data Addr. Data Addr. Data
Read/Reset*
1
XXXH F0H
—
—
—
—
—
—
—
—
—
—
Reset/Read*
3
XXXH AAH XXXH
55H
XXXH F0H
RA
RD
—
—
—
—
Autoselect
3
XXXH AAH XXXH
55H
XXXH
90H
—
—
—
—
—
—
Byte Program
4
XXXH AAH XXXH
55H
XXXH A0H
PA
PD
—
—
—
—
Chip Erase
6
XXXH AAH XXXH
55H
XXXH
80H
XXXH AAH XXXH
55H
XXXH
10H
Sector Erase
6
XXXH AAH XXXH
55H
XXXH
80H
XXXH AAH XXXH
55H
SA
30H
Sector Erase
Suspend
1
Erase can be suspended during sector erase with Addr (“H” or “L”). Data (B0H)
Sector Erase
Resume
1
Erase can be resumed after suspend with Addr (“H” or “L”). Data (30H)