M28R400C View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

M28R400C

4 Mbit (256Kb x16, Boot Block) 1.8V Supply Flash Memory

STMicroelectronics 

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M28R400CT, M28R400CB

Figure 20. Locking Operations Flowchart and Pseudo Code

Start

Write 60h

Write

01h, D0h or 2Fh

Write 90h

Read Block

Lock States

Locking

NO

change

confirmed?

YES

Write FFh

End

locking_operation_command (address, lock_operation) {

writeToFlash (any_address, 0x60) ; /*configuration setup*/

if (lock_operation==LOCK) /*to protect the block*/

writeToFlash (address, 0x01) ;

else if (lock_operation==UNLOCK) /*to unprotect the block*/

writeToFlash (address, 0xD0) ;

else if (lock_operation==LOCK-DOWN) /*to lock the block*/

writeToFlash (address, 0x2F) ;

writeToFlash (any_address, 0x90) ;

if (readFlash (address) ! = locking_state_expected)

error_handler () ;

/*Check the locking state (see Read Block Signature table )*/

writeToFlash (any_address, 0xFF) ; /*Reset to Read Array mode*/

}

AI04364

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