Fujitsu FR81S User Manual
CHAPTER 45: FLASH MEMORY
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : FLASH MEMORY
FUJITSU SEMICONDUCTOR CONFIDENTIAL
31
Note:
If an incorrect address value or data value is written, or an incorrect sequence is written, the
commands written till then will be cleared.
Reset Command
Each command input shown in Table 5-1 input to send the reset command to the object flash memory till
then can try to be canceled, and to input the command from the first time again.
However, when each command is input to the last minute and automatic algorithm starts, automatic
algorithm cannot be discontinued by this reset command.
If the execution of the automatic algorithm exceeds the timing limit, the flash memory returns to the reset
state if the reset command is input.
Read Command
The flash memory can be read by sending the reading command to the target sector. If the read command is
issued, the flash memory stays in read state until another command is issued.
Program (Write) Command
If a write command is sent to the target sector four times in a row, the automatic algorithm starts and writes
data to the flash memory. Programming (writing) of data can be performed in any order of addresses or
across a sector boundary.
In CPU programming mode, data is written in half-words or bytes. Once the fourth write has finished, the
automatic algorithm starts and the automatic write to flash memory is started. After executing the automatic
write algorithm command sequence, there is no need to control the flash memory externally.
See "5.5. Write Command" for details on the actual operation.
Notes:
- If the fourth write command (write data cycle) is written to an odd address when writing in half-word, the
write is not performed correctly. Always write to an even address.
- In the first write command sequence, only a single half-word data can be written. If you want to write
multiple data, issue one write command sequence for each data.
- When security is ON, there are restrictions in the procedure for writing the flash. See "5.9.4. Flash
Access Restrictions When Security is ON" for details.
MB91520 Series
MN705-00010-1v0-E
1952