Fujitsu MB90335 Series Hardware Manual page 507

CHAPTER 22 DUAL OPERATION FLASH MEMORY
22.3 Registers of Flash Memory
Table 22.3-2 Functions of Flash Memory Write Control Register (FWR0/FWR1)
Bit Name
bit15 to
Reserved: Reserved bits
bit10
SA9E to SA0E:
Accidental write
bit9 to bit0
preventive function
setting bits
486
Always set these bits to "0". The reading value is irregular.
These bits are used to set the accidental write preventive function for the
individual sectors of the flash memory. Writing "1" to each of the bits write-
enables the corresponding sector. Writing "0" to the bit activates the accidental
write preventive function for the sector.
Resetting the bit initializes it to "0" (write-protecting the sector).
Accidental write preventive function setting bits and flash memory sectors
Bit
9
8
7
6
5
4
3
2
1
0
Write-protected: "0" status. "0" has not been written to the flash memory
write control register (FWR0/FWR1), where you can write
"1" to the register bit for each sector to write-enable the
sector. (after reset state)
Write-enabled: "1" status. Data can be written to the corresponding sector.
Accidental write preventive:
"0" status. "0" has been written to the flash memory write control
register (FWR0/FWR1), where the corresponding sector cannot be
write-enabled ("1") even though "1" is written to the register bit.
FUJITSU MICROELECTRONICS LIMITED
MB90335 Series
Function
Bit name Flash memory sector
SA9E SA9
SA8E SA8
SA7E SA7
SA6E SA6
SA5E SA5
SA4E SA4
SA3E SA3
SA2E SA2
SA1E SA1
SA0E SA0
CM44-10137-6E