M28W320 データシートの表示（PDF） - STMicroelectronics

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M28W320

32 Mbit (2Mb x16, Boot Block) 3V Supply Flash Memory

STMicroelectronics 

M28W320FCT, M28W320FCB

Status Register

6.3

Erase Status (Bit 5)

The Erase Status bit can be used to identify if the memory has failed to verify that the block

has erased correctly. When the Erase Status bit is High (set to ‘1’), the Program/Erase

Controller has applied the maximum number of pulses to the block and still failed to verify

that the block has erased correctly. The Erase Status bit should be read once the

Program/Erase Controller Status bit is High (Program/Erase Controller inactive).

Once set High, the Erase Status bit can only be reset Low by a Clear Status Register

command or a hardware reset. If set High it should be reset before a new Program or Erase

command is issued, otherwise the new command will appear to fail.

6.4

Program Status (Bit 4)

The Program Status bit is used to identify a Program failure. When the Program Status bit is

High (set to ‘1’), the Program/Erase Controller has applied the maximum number of pulses

to the byte and still failed to verify that it has programmed correctly. The Program Status bit

should be read once the Program/Erase Controller Status bit is High (Program/Erase

Controller inactive).

Once set High, the Program Status bit can only be reset Low by a Clear Status Register

command or a hardware reset. If set High it should be reset before a new command is

issued, otherwise the new command will appear to fail.

6.5

VPP Status (Bit 3)

The VPP Status bit can be used to identify an invalid voltage on the VPP pin during Program

and Erase operations. The VPP pin is only sampled at the beginning of a Program or Erase

operation. Indeterminate results can occur if VPP becomes invalid during an operation.

When the VPP Status bit is Low (set to ‘0’), the voltage on the VPP pin was sampled at a valid

voltage; when the VPP Status bit is High (set to ‘1’), the VPP pin has a voltage that is below

the VPP Lockout Voltage, VPPLK, the memory is protected and Program and Erase

operations cannot be performed.

Once set High, the VPP Status bit can only be reset Low by a Clear Status Register

command or a hardware reset. If set High it should be reset before a new Program or Erase

command is issued, otherwise the new command will appear to fail.

6.6

Program Suspend Status (Bit 2)

The Program Suspend Status bit indicates that a Program operation has been suspended.

When the Program Suspend Status bit is High (set to ‘1’), a Program/Erase Suspend

command has been issued and the memory is waiting for a Program/Erase Resume

command. The Program Suspend Status should only be considered valid when the

Program/Erase Controller Status bit is High (Program/Erase Controller inactive). Bit 2 is set

within 5µs of the Program/Erase Suspend command being issued therefore the memory

may still complete the operation rather than entering the Suspend mode.

When a Program/Erase Resume command is issued the Program Suspend Status bit

returns Low.

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