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19.6
Reset Vector Addresses in Flash Memory
The MB90F897 uses hardwired reset vectors.
In CPU mode, any read access to addresses FFFFDCH to FFFFDFH returns a hardware-
fixed value. In flash memory mode, by contrast, these addresses are accessible.
Writing to these addresses is therefore meaningless. When programming the flash
memory by CPU access, in particular, do not read these addresses by software polling.
In that case, fixed reset vector values are read in place of flash memory status flag
values.
I Hardwired Reset Vector Addresses
Table 19.6-1 lists reset vectors and mode data fixed values.
Table 19.6-1 Reset Vectors and Mode Data Fixed Values
Reset Vector
Mode Data
Note:
Reset vectors and mode data have values indicated as above, so values of them in the program written to
flash memory have no effect on operation. However, when using the same program in mask ROM, it is
possible to operate differently, therefore, be sure to write the same data to flash memory.
CHAPTER 19 512 KBIT FLASH MEMORY
Address
Data (Fixed Value)
FFFFDC
H
FFFFDD
H
FFFFDE
H
FFFFDF
H
00
H
E0
H
FF
H
00
H
589
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