M50FW016 Datasheet, PDF (18/45 Pages) STMicroelectronics – 16 Mbit 2Mb x8, Uniform Block 3V Supply Firmware Hub Flash Memory

M50FW016
start address and four data bytes in the internal
state machine and starts 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 on the definitions of the
Status Register bits.
During the Quadruple Byte Program operation the
memory will only accept the Read Status register
command and the Program/Erase Suspend com-
mand. All other commands will be ignored. Typical
Quadruple Byte Program times are given in Table
15.
Note that the Quadruple Byte Program command
cannot change a bit set to ‘0’ back to ‘1’ and
attempting to do so will not cause any modification
on its value. One of the Erase commands must be
used to set all of the bits in the block to ‘1’.
See Figure 18., for a suggested flowchart on using
the Quadruple Byte Program command.
Chip Erase Command. The Chip Erase Com-
mand can be only used in A/A Mux mode to erase
the entire chip at a time. Erasing should not be at-
tempted when V_PP is not at V_PPH. The operation
can also be executed if V_PP is below V_PPH, 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 on the definitions of the Sta-
tus Register bits. During the Chip Erase operation
the memory will only accept the Read Status Reg-
ister command. All other commands will be ig-
nored. Typical Chip Erase times are given in Table
15. The Chip Erase command sets all of the bits in
the memory to ‘1’. See Figure 20., Chip Erase
Flowchart and Pseudo Code (A/A Mux Interface
Only), for a suggested flowchart on 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 Sta-
tus Register bits.
If the block is protected then the Block Erase
operation will abort, the data in the block will not be
changed and the Status Register will output the
error.
During the Block Erase operation the memory will
only accept the Read Status Register command
and the Program/Erase Suspend command. All
other commands will be ignored. Typical Block
Erase times are given in Table 15.
The Block Erase command sets all of the bits in
the block to ‘1’. All previous data in the block is
lost.
See Figure 21., Block Erase Flowchart and
Pseudo Code, 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 Block Erase operation. One
Bus Write cycle is required to issue the Program/
Erase Suspend command and pause the Pro-
gram/Erase Controller. Once the command is is-
sued it is necessary 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 Control-
ler has paused. After the Program/Erase Control-
ler has paused, the memory will continue to output
the Status Register until another command is is-
sued.
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 15.
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 Block Erase then the Program command will
also be accepted; only the blocks not being erased
may be read or programmed correctly.
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