MBM29DL640E Fujitsu Microelectronics, Inc., MBM29DL640E Datasheet - Page 28

• Manufacturer Part Number: MBM29DL640E
• Description: Flash Memory 64 M 8 M X 8/4 M X 16 Bit Dual Operation
• Manufacturer: Fujitsu Microelectronics, Inc.

28
MBM29DL640E
Read/Reset Command
Autoselect Command
COMMAND DEFINITIONS
Device operations are selected by writing specific address and data sequences into the command register. Some
commands require Bank Address (BA) input. When command sequences are input into a bank reading, the
commands have priority over the reading. Table 4 shows 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. Also the Program Suspend (B0h) and Program Resume (30h) commands are valid only while the
Program operation is in progress. Moreover, Read/Reset commands are functionally equivalent, resetting the
device to the read mode. Please note that commands are always written at DQ
are ignored.
In order to return from Autoselect mode or Exceeded Timing Limits (DQ
Reset operation is initiated by writing the Read/Reset command sequence into the command register. Micro-
processor read cycles retrieve array data from the memory. The device remains enabled for reads until the
command register contents are altered.
The device will automatically power-up in the Read/Reset state. In this case a command sequence is not required
in order 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 AC Read Char-
acteristics and Timing Diagram for the specific timing parameters.
Flash memories are intended for use in applications where the local CPU alters memory contents. Therefore,
manufacture and device codes must be accessible while the device resides in the target system. PROM pro-
grammers 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 method-
ology. The operation is initiated by writing the Autoselect command sequence into the command register.
The Autoselect command sequence is initiated first by writing two unlock cycles. This is followed by a third write
cycle that contains the bank address (BA) and the Autoselect command. Then the manufacture and device
codes can be read from the bank, and actual data from the memory cell can be read from another bank. The
higher order address (A
bank address (BA) set at the third write cycle.
Following the command write, in WORD mode, a read cycle from address (BA) 00h returns the manufacturer’s
code (Fujitsu
indicates that two additional codes, called Extended Device Codes will be required. Therefore the system may
continue reading out these Extended Device Codes at the address of (BA) 0Eh, as well as at (BA) 0Fh. Notice
Scanning the sector group addresses (A
verification should be performed by verifying sector group protection on the protected sector. (See Tables 2 and 3.)
The manufacture and device codes can be read from the selected bank. To read the manufacture and device
codes and sector protection status from a non-selected bank, it is necessary to write the Read/Reset command
sequence into the register. Autoselect command should then be written into the bank to be read.
If the software (program code) for Autoselect command is stored in the Flash memory, the device and manu-
that the above applies to WORD mode. The addresses and codes differ from those of BYTE mode. (Refer to
Table 5.1 and 5.2. )
The sector state (protection or unprotection) will be informed by address (BA) 02h for
facture codes should be read from the other bank, which does not contain the software.
To terminate the operation, it is necessary to write the Read/Reset command sequence into the register. To
execute the Autoselect command during the operation, Read/Reset command sequence must be written before
the Autoselect command.
(0, 0, 0, 1, 0) will produce a logical “1” at device output DQ
04h) . And a read cycle at address (BA) 01h outputs device code. When 227Eh was output, this
21
, A
20
, A
80/90/12
19
) required for reading out the manufacture and device codes demands the
21
, A
20
, A
19
, A
18
, A
17
, A
9
0
16
to a higher voltage. However, multiplexing high
for a protected sector group. The programming
, A
15
, A
14
, A
5
13
1) to Read/Reset mode, the Read/
, and A
7
to DQ
12
) while (A
0
16 ( (BA) 04h for
and DQ
6
, A
15
3
, A
to DQ
2
, A
8
1
, A
bits
8) .
0
)