M58LW032A 데이터 시트보기 (PDF) - STMicroelectronics

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M58LW032A

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

STMicroelectronics 

M58LW032A

STATUS REGISTER

The Status Register provides information on the

current or previous Program, Erase, Block Protect

or Blocks Unprotect operation. The various bits in

the Status Register convey information and errors

on the operation. They are output on DQ7-DQ0.

To read the Status Register the Read Status Reg-

ister command can be issued. The Status Register

is automatically read after Program, Erase, Block

Protect, Blocks Unprotect and Program/Erase Re-

sume commands. The Status Register can be

read from any address.

The Status Register can only be read using Asyn-

chronous Bus Read operations. Once the memory

returns to Read Memory Array mode the bus will

resume the setting in the Burst Configuration Reg-

ister automatically.

The contents of the Status Register can be updat-

ed during an Erase or Program operation by tog-

gling the Output Enable pin or by dis-activating

(Chip Enable, VIH) and then reactivating (Chip En-

able and Output Enable, VIL) the device.

Status Register bits 5, 4, 3 and 1 are associated

with various error conditions and can only be reset

with the Clear Status Register command. The Sta-

tus Register bits are summarized in Table 10, Sta-

tus Register Bits. Refer to Table 10 in conjunction

with the following text descriptions.

Program/Erase Controller Status (Bit 7). The Pro-

gram/Erase Controller Status bit indicates whether

the Program/Erase Controller is active or inactive.

When the Program/Erase Controller Status bit is

Low, VOL, the Program/Erase Controller is active

and all other Status Register bits are High Imped-

ance; when the bit is High, VOH, the Program/

Erase Controller is inactive.

The Program/Erase Controller Status is Low im-

mediately after a Program/Erase Suspend com-

mand is issued until the Program/Erase Controller

pauses. After the Program/Erase Controller paus-

es the bit is High.

During Program, Erase, Block Protect and Blocks

Unprotect operations the Program/Erase Control-

ler Status bit can be polled to find the end of the

operation. The other bits in the Status Register

should not be tested until the Program/Erase Con-

troller completes the operation and the bit is High.

After the Program/Erase Controller completes its

operation the Erase Status, Program Status and

Block Protection Status bits should be tested for

errors.

Erase Suspend Status (Bit 6). The Erase Sus-

pend Status bit indicates that an Erase operation

has been suspended and is waiting to be re-

sumed. The Erase Suspend Status should only be

considered valid when the Program/Erase Con-

troller Status bit is High (Program/Erase Controller

inactive); after a Program/Erase Suspend com-

mand is issued the memory may still complete the

operation rather than entering the Suspend mode.

When the Erase Suspend Status bit is Low, VOL,

the Program/Erase Controller is active or has com-

pleted its operation; when the bit is High, VOH, a

Program/Erase Suspend command has been is-

sued and the memory is waiting for a Program/

Erase Resume command.

When a Program/Erase Resume command is is-

sued the Erase Suspend Status bit returns Low.

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 or that all

blocks have been unprotected successfully. The

Erase Status bit should be read once the Program/

Erase Controller Status bit is High (Program/Erase

Controller inactive).

When the Erase Status bit is Low, VOL, the mem-

ory has successfully verified that the block has

erased correctly or all blocks have been unprotect-

ed successfully. When the Erase Status bit is

High, VOH, the erase operation has failed. De-

pending on the cause of the failure other Status

Register bits may also be set to High, VOH.

s If only the Erase Status bit (bit 5) is set High,

VOH, then 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 or that all the blocks have been

unprotected successfully.

s If the failure is due to an erase or blocks

unprotect with VPP low, VOL, then VPP Status bit

(bit 3) is also set High, VOH.

s If the failure is due to an erase on a protected

block then Block Protection Status bit (bit 1) is

also set High, VOH.

s If the failure is due to a program or erase

incorrect command sequence then Program

Status bit (bit 4) is also set High, VOH.

Once set High, the Erase Status bit can only be re-

set Low by a Clear Status Register command or a

hardware reset. If set High it should be reset be-

fore a new Program or Erase command is issued,

otherwise the new command will appear to fail.

Program Status (Bit 4). The Program Status bit

is used to identify a Program or Block Protect fail-

ure. The Program Status bit should be read once

the Program/Erase Controller Status bit is High

(Program/Erase Controller inactive).

When the Program Status bit is Low, VOL, the

memory has successfully verified that the Write

Buffer has programmed correctly or the block is

protected. When the Program Status bit is High,

VOH, the program or block protect operation has

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