LRS1383 View Datasheet(PDF) - Sharp Electronics
Part Name
Description
MFG CO.
'LRS1383' PDF : 114 Pages View PDF
LRS1383
35
16. Flash Memory Data Protection
Noises having a level exceeding the limit specified in the specification may be generated under specific operating conditions on
some systems. Such noises, when induced onto F-WE signal or power supply, may be interpreted as false commands, causing
undesired memory updating. To protect the data stored in the flash memory against unwanted writing, systems operating with the
flash memory should have the following write protect designs, as appropriate.
The below describes data protection method.
1. Protecting data in specific block
• Any locked block by setting its block lock bit is protected against the data alternation. When F-WP is VIL, any locked-
down block by setting its block lock-down bit is protected from lock status changes. By using this function, areas can be
defined, for example, program area (locked blocks), and data area (unlocked blocks).
• For detailed block locking scheme, see Chapter 5. Command definitions for Flash Memory.
2. Data Protection through F-VPP
• When the level of F-VPP is lower than VPPLK (lockout voltage), write operation on the flash memory is disabled. All
blocks are locked and the data in the blocks are completely write protected.
• For the lockout voltage, refer to the specification. (See Chapter 11. DC Electrical Characteristics)
Data Protection during voltage transition
1. Data protection thorough F-RST
• When the F-RST is kept low during power up and power down sequence, write operation on the flash memory is
disabled, write protecting all blocks.
• For the details of F-RST control, refer to the specification.
(See Chapter 12.6 AC Electrical Characteristics for Flash Memory)
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