CHAPTER 3 CPU AND CONTROL UNITS
In the FR family microcontrollers, the mode pins (MD2, MD1, and MD0) and the mode
register (MODR) are used to set the operating mode.
■ Mode Pins
Use the three mode pins (MD2, MD1, and MD0) to specify mode vector fetch.
Table 3.8-1 lists the specifications related to mode vector fetch.
Table 3.8-1 Specifications Related to Mode Vector Fetch
Settings not listed in the table above are not allowed.
■ Mode Register (MODR)
Mode data is data written to the mode register by a mode vector fetch. For the mode vector fetch, see
(Section "3.9.3 Reset Sequence").
After the data is set to the mode register (MODR), it operates in the operating mode according to this
Mode data is always set in the mode register when any reset source arises. A user program cannot write
data to the mode register.
Nothing exists at the address (0000_07FF
Data can be rewritten to the mode register in emulator mode. Use an 8-bit long data transfer instruction to
A 16-bit or 32-bit long data transfer instruction cannot be used to rewrite data to the mode register.
Details of the mode register are given below:
Internal ROM mode
External ROM mode
) of the mode register in conventional FR family
Set the bus width using the