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CHAPTER 17 FLASH MEMORY
Note:
When automatic algorithm operation is close to its end, bit7 (data polling) is changed asynchronously
during read operation. This means that the flash memory sends the operation status information to
bit7 and the bit7 sends the defined data to the next. When the flash memory ends the automatic
algorithm and even if the bit7 outputs the defined data, other bits are undefined. Defined data of
other bits is read when executing consecutive read operation.
[bit6] TOGGLE: Toggle bit
• Automatic write/erase operation status
When continuous read operations are performed while the automatic write or erase algorithm is being
executed, flash memory outputs "1" and "0" toggling results to bit6.
algorithm ends, flash memory stops bit6 from toggling to continuous read operations and outputs valid
data.
Toggle bit becomes valid after the last write cycle of each command sequence.
If sectors to be written are rewrite assured sectors, the toggle operation ends after about 2 µs toggling
period without rewriting data. When erasing, if the all selected sectors are write assured sectors, the
operation returns into the read mode after about 100 µs toggling period without rewriting data.
• Temporary sector erase stop status
When a read operation is performed during a temporary sector erase stop operation, flash memory
outputs "1" if the address indicated by the address signal belongs to the sector in erase state. If not, flash
memory outputs bit6 of the read value at the address indicated by the address signal.
[bit5] TLOVER: Time limit over
• Automatic write/erase operation status
bit5 indicates that automatic algorithm is executed beyond the time (internal pulse count) specified
inside the flash memory. In this case, bit5 outputs "1". In other words, if this flag outputs "1" during
automatic algorithm execution, it indicates that write or erase operation fails.
In addition, bit5 fails when writing into the non-blank without erasing. In this case, defined data cannot
be read from bit7 (data polling), and bit6 keeps toggling. If the operation exceeds the time limit in this
condition, "1" is output to bit5. This status indicates that flash memory was not used correctly, not that
it was defective. Be sure to execute the reset command if this state appears.
422
When automatic write or erase
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