lrs1383 Sharp Microelectronics of the Americas, lrs1383 Datasheet - Page 37

• Manufacturer Part Number: lrs1383
• Description: Stacked Chip 32m Flash And 8m Sram
• Manufacturer: Sharp Microelectronics of the Americas

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.
Data Protection during voltage transition
1. Protecting data in specific block
2. Data Protection through F-V
1. Data protection thorough F-RST
• Any locked block by setting its block lock bit is protected against the data alternation. When F-WP is V
• For detailed block locking scheme, see Chapter 5. Command definitions for Flash Memory.
• When the level of F-V
• For the lockout voltage, refer to the specification. (See Chapter 11. DC Electrical Characteristics)
• When the F-RST is kept low during power up and power down sequence, write operation on the flash memory is
• For the details of F-RST control, refer to the specification.
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).
blocks are locked and the data in the blocks are completely write protected.
disabled, write protecting all blocks.
(See Chapter 12.6 AC Electrical Characteristics for Flash Memory)
PP
PP
is lower than V
PPLK
(lockout voltage), write operation on the flash memory is disabled. All
L R S1 3 8 3
IL
, any locked-
35