M50FW002 データシートの表示（PDF） - STMicroelectronics
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M50FW002 Datasheet PDF : 39 Pages
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M50FW002
for a suggested flowchart on using the Quadruple
Byte Program command.
Chip Erase Command. The Chip Erase com-
mand can be used in A/A Mux mode to erase the
entire chip at a time. Erasing should not be at-
tempted when VPP is not at VPPH. The operation
can also be executed if VPP is below VPPH, but re-
sult could be uncertain. Two Bus Write operations
are required to issue the command and start the
Program/Erase Controller. Once the command is
issued, subsequent Bus Read operations read the
Status Register. (See the section on the Status
Register for details of the definitions of the Status
Register bits.)
During the Chip Erase operation, the memory only
accepts the Read Status Register command. All
other commands are ignored.
Typical Chip Erase times are given in Table 22.
The Chip Erase command sets all of the bits in the
memory to ‘1’. See Figure 17, Chip Erase Flow-
chart and Pseudo Code, for a suggested flowchart
when using the Chip Erase command.
Block Erase Command. The Block Erase com-
mand can be used to erase a block. Two Bus Write
operations are required to issue the command; the
second Bus Write cycle latches the block address
in the internal state machine and starts the Pro-
gram/Erase Controller. Once the command is is-
sued subsequent Bus Read operations read the
Status Register. See the section on the Status
Register for details on the definitions of the Status
Register bits.
If the block is protected then the Erase operation
will abort, the data in the block will not be changed
and the Status Register will output the error.
During the Erase operation the memory only
accepts the Read Status Register command and
the Program/Erase Suspend command. All other
commands are ignored. Typical Erase times are
given in Table 22.
The Erase command sets all of the bits in the block
to ‘1’. All previous data in the block is lost.
See Figure 18, for a suggested flowchart on using
the Erase command.
Clear Status Register Command. The Clear Sta-
tus Register command can be used to reset bits 1,
3, 4 and 5 in the Status Register to ‘0’. One Bus
Write is required to issue the Clear Status Register
command. Once the command is issued the mem-
ory returns to its previous mode, subsequent Bus
Read operations continue to output the same data.
The bits in the Status Register are sticky and do
not automatically return to ‘0’ when a new Program
or Erase command is issued. If an error occurs
then it is essential to clear any error bits in the Sta-
tus Register by issuing the Clear Status Register
command before attempting a new Program or
Erase command.
Program/Erase Suspend Command. The Pro-
gram/Erase Suspend command can be used to
pause a Program or Erase operation. One Bus
Write cycle is required to issue the Program/Erase
Suspend command and pause the Program/Erase
Controller. Once the command is issued it is nec-
essary to poll the Program/Erase Controller Status
bit to find out when the Program/Erase Controller
has paused; no other commands will be accepted
until the Program/Erase Controller has paused.
After the Program/Erase Controller has paused,
the memory will continue to output the Status Reg-
ister until another command is issued.
During the polling period between issuing the
Program/Erase Suspend command and the
Program/Erase Controller pausing it is possible for
the operation to complete. Once Program/Erase
Controller Status bit indicates that the Program/
Erase Controller is no longer active, the Program
Suspend Status bit or the Erase Suspend Status
bit can be used to determine if the operation has
completed or is suspended. For timing on the
delay between issuing the Program/Erase
Suspend command and the Program/Erase
Controller pausing see Table 22.
During Program/Erase Suspend the Read
Memory Array, Read Status Register, Read
Electronic Signature and Program/Erase Resume
commands will be accepted by the Command
Interface. Additionally, if the suspended operation
was Erase then the Program command will also be
accepted; only the blocks not being erased may be
read or programmed correctly.
See Figures 16, Program Suspend and Resume
Flowchart, and Pseudo Code, and 19, Erase
Suspend and Resume Flowchart, and Pseudo
Code, for suggested flowcharts on using the
Program/Erase Suspend command.
Program/Erase Resume Command. The Pro-
gram/Erase Resume command can be used to re-
start the Program/Erase Controller after a
Program/Erase Suspend has paused it. One Bus
Write cycle is required to issue the Program/Erase
Resume command. Once the command is issued
subsequent Bus Read operations read the Status
Register.
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