MBM29LV002TC-70 Meet Spansion Inc., MBM29LV002TC-70 Datasheet - Page 16

• Manufacturer Part Number: MBM29LV002TC-70
• Description: Flash Memory Cmos 2m 256k ? 8 Bit
• Manufacturer: Meet Spansion Inc.

16
MBM29LV002TC
Temporary Sector Unprotection
Command Definitions
Read/Reset Command
Autoselect Command
This feature allows temporary unprotection of previously protected sectors of the MBM29LV002TC/BC devices
in order to change data. The Sector Unprotection mode is activated by setting the RESET pin to high voltage
(12 V). During this mode, formerly protected sectors can be programmed or erased by selecting the sector
addresses. Once the 12 V is taken away from the RESET pin, all the previously protected sectors will be protected
again. See “ (11) Temporary Sector Unprotection Timing Diagram” in ■ TIMING DIAGRAM and “ (6) Temporary
Sector Unprotection Algorithm” in ■ FLOW CHART.
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 devices to the
read mode. “MBM29LV002TC/002BC Standard Command Definitions” in ■ DEVICE BUS OPERATION 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.
In order to return from Autoselect mode or Exceeded Timing Limits (DQ
operation is initiated by writing the Read/Reset command sequence into the command register. Microprocessor
read cycles retrieve array data from the memory. The devices remain enabled for reads until the command
register contents are altered.
The devices will automatically power-up in the read/reset state. In this case, a command sequence is not required
to read data. Standard microprocessor read cycles will retrieve array data. This default value ensures that no
spurious alteration of the memory content occurs during the power transition. Refer to the AC Read
Characteristics and Waveforms for the specific timing parameters.
Flash memories are intended for use in applications where the local CPU alters memory contents. As such,
manufacture and device codes must be accessible while the devices reside in the target system. PROM
programmers typically access the signature codes by raising A
voltage onto the address lines is not generally desired system design practice.
The device contains an Autoselect command operation to supplement traditional PROM programming
methodology. The operation is initiated by writing the Autoselect command sequence into the command register.
Following the command write, a read cycle from address XX00h retrieves the manufacture code of 04h. A read
cycle from address XX01h returns the device code (MBM29LV002TC = 40h and MBM29LV002BC = C2h). (See
“MBM29LV002TC/002BC Sector Protection Verify Autoselect Codes” and “Expanded Autoselect Code Table”
in ■ DEVICE BUS OPERATION.) All manufacturer and device codes will exhibit odd parity with DQ
the parity bit. Sector state (protection or unprotection) will be informed by address XX02h.
Scanning the sector addresses (A
logical “1” at device output DQ
mode on the protected sector. (See “MBM29LV002TC/002BC User Bus Operation”, “MBM29LV002TC/002BC
Sector Protection Verify Autoselect Codes” and “Expanded Autoselect Code Table” in ■ DEVICE BUS
OPERATION.)
To terminate the operation, it is necessary to write the Read/Reset command sequence into the register, and
also to write the Autoselect command during the operation, execute it after writing Read/Reset command
sequence.
0
-70/-90
for a protected sector. The programming verification should be perform margin
17
, A
Retired Product DS05-20863-5E_July 26, 2007
16
/MBM29LV002BC
, A
15
, A
14
, and A
13
) while (A
9
to a high voltage. However, multiplexing high
10
, A
5
6
= 1) to read/reset mode, the read/reset
, A
1
, A
-70/-90
0
) = (0, 0, 1, 0) will produce a
7
defined as