Fujitsu F2MC-16LX Hardware Manual page 124

CHAPTER 4 RESET
I Mode fetch
After a reset is canceled, the CPU transfers the reset vectors and mode data to the applicable
registers in the CPU core. The reset vectors and mode data are allocated to four bytes, namely
FFFFDC
addresses to a bus and fetches reset vectors and mode data. During mode fetching, the CPU
starts processing beginning from the address specified by the reset vector.
Figure 4.4-2 "Transfer of reset vectors and mode data" shows transfer of reset vectors and
mode data.
FFFFDF
FFFFDE
FFFFDD
FFFFDC
Reference:
Use a mode pin, from which reset vectors and mode data are read, to specify either internal
ROAM or external memory. If the external vector mode is specified with a mode pin,
however, external memory and not internal ROM is accessed to read reset vectors and
mode data. Fujitsu recommends specifying the internal vector mode with a mode pin when
the single-chip mode and internal ROM external bus mode are used.
❍ Mode data (Address: FFFFDF
The data in the mode register can be modified only by a reset, and the mode register settings
become effective after a reset. Refer to Section 7.3 "Mode Data", for details on mode data.
❍ Reset vector (Address: FFFFDC
Write the execution start address after the end of a reset. Execution starts from this address.
108
to FFFFDF . Upon a reset cancellation, the CPU immediately outputs these
H H
Figure 4.4-2 Transfer of reset vectors and mode data
Memory space
Mode data
H
Reset vector bits 23 to 16
H
Reset vector bits 15 to 8
H
Reset vector bits 7 to 0
H
)
H
2
F MC-16LX CPU Core
to FFFFDE )
H H
Mode
register
Micro ROM
Sequence for
resetting
PCB
PC