M29W640FB STMICROELECTRONICS [STMicroelectronics], M29W640FB Datasheet - Page 25

• Manufacturer Part Number: M29W640FB
• Description: 64 Mbit (8Mb x8 or 4Mb x16, Page, Boot Block) 3V Supply Flash Memory
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M29W640FT, M29W640FB
4.2.5
4.2.6
4.2.7
4.2.8
Quadruple Word Program command
This is used to write a page of four adjacent Words (or 8 adjacent Bytes), in x16 mode,
simultaneously. The addresses of the four Words must differ only in A1 and A0.
Five bus write cycles are necessary to issue the command:
Unlock Bypass command
The Unlock Bypass command is used in conjunction with the Unlock Bypass Program
command to program the memory faster than with the standard program commands. When the
cycle time to the device is long, considerable time saving can be made by using these
commands. Three Bus Write operations are required to issue the Unlock Bypass command.
Once the Unlock Bypass command has been issued the memory will only accept the Unlock
Bypass Program command and the Unlock Bypass Reset command. The memory can be read
as if in Read mode.
When V
Bypass mode and the Unlock Bypass Program command can be issued immediately.
Unlock Bypass Program command
The Unlock Bypass command is used in conjunction with the Unlock Bypass Program
command to program the memory. When the cycle time to the device is long, considerable time
saving can be made by using these commands. Three Bus Write operations are required to
issue the Unlock Bypass command.
Once the Unlock Bypass command has been issued the memory will only accept the Unlock
Bypass Program command and the Unlock Bypass Reset command. The memory can be read
as if in Read mode.
The memory offers accelerated program operations through the V
the system asserts V
Unlock Bypass mode. The system may then write the two-cycle Unlock Bypass program
command sequence. The memory uses the higher voltage on the V
accelerate the Unlock Bypass Program operation.
Never raise V
memory may be left in an indeterminate state.
Unlock Bypass Reset command
The Unlock Bypass Reset command can be used to return to Read/Reset mode from Unlock
Bypass Mode. Two Bus Write operations are required to issue the Unlock Bypass Reset
command. Read/Reset command does not exit from Unlock Bypass Mode.
The first bus cycle sets up the command.
The second bus cycle latches the Address and the Data of the first Word to be written.
The third bus cycle latches the Address and the Data of the second Word to be written.
The fourth bus cycle latches the Address and the Data of the third Word to be written.
The fifth bus cycle latches the Address and the Data of the fourth Word to be written and
starts the Program/Erase Controller.
PP
is applied to the V
PP
/Write Protect to V
PP
on the V
PP
/Write Protect pin the memory automatically enters the Unlock
PP
PP
/Write Protect pin, the memory automatically enters the
from any mode except Read mode, otherwise the
PP
PP
/Write Protect pin. When
/Write Protect pin, to
4 Command Interface
25/72