M29W008EB データシートの表示（PDF） - STMicroelectronics

部品番号

コンポーネント説明

メーカー

M29W008EB

8 Mbit (1Mb x 8, Boot Block) 3V Supply Flash Memory

STMicroelectronics 

4 Command interface

4 Command interface

M29W008ET, M29W008EB

All Bus Write operations to the memory are interpreted by the Command Interface.

Commands consist of one or more sequential Bus Write operations. Failure to observe a valid

sequence of Bus Write operations will result in the memory returning to Read mode. The long

command sequences are imposed to maximize data security. All commands start with two

coded cycles which unlock the Command Interface.

Seven commands are available: Read/Reset, Auto Select (to read the Electronic Signature and

the Block Protection Status), Program, Block Erase, Chip Erase, Erase Suspend and Erase

Resume (see Table 3: Commands).

4.1 Read/Reset command

The Read/Reset command returns the memory to its Read mode where it behaves like a ROM

or EPROM, unless otherwise stated. It also resets the errors in the Status Register. Either one

or three Bus Write operations can be used to issue the Read/Reset command.

The Read/Reset Command can be issued, between Bus Write cycles before the start of a

program or erase operation, to return the device to read mode. Once the program or erase

operation has started the Read/Reset command is no longer accepted. The Read/Reset

command will not abort an Erase operation when issued while in Erase Suspend.

4.2 Auto Select command

The Auto Select command is used to read the Manufacturer Code, the Device Code and the

Block Protection Status. Three consecutive Bus Write operations are required to issue the Auto

Select command. Once the Auto Select command is issued the memory remains in Auto Select

mode until another command is issued.

From the Auto Select mode the Manufacturer Code can be read using a Bus Read operation

with A0 = VIL and A1 = VIL. The other address bits may be set to either VIL or VIH.

The Device Code can be read using a Bus Read operation with A0 = VIH and A1 = VIL. The

other address bits may be set to either VIL or VIH.

The Block Protection Status of each block can be read using a Bus Read operation with A0 =

VIL, A1 = VIH, and A13-A19 specifying the address of the block. The other address bits may be

set to either VIL or VIH. If the addressed block is protected then 01h is output on Data Inputs/

Outputs DQ0-DQ7, otherwise 00h is output.

4.3 Program command

The Program command can be used to program a value to one address in the memory array at

a time. The command requires four Bus Write operations, the final write operation latches the

address and data and starts the Program/Erase Controller.

If the address falls in a protected block then the Program command is ignored, the data

remains unchanged. The Status Register is never read and no error condition is given.

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