CHAPTER 3 CPU AND CONTROL UNITS
3.9
Operation Modes
Operation modes of the MB91260B series are divided into bus modes and access
modes.
However, only single chip mode is supported.
■ Operation Modes
●
Bus mode
Bus mode controls the operations of internal ROM and the external access functions according to the mode
pins (MD2 to MD0).
Note:
The MB91260B series does not support the external bus mode.
■ Bus Modes
See Section 3.6 "Memory Map".
●
Single-chip mode
This mode enables access to internal I/O, internal RAM, and internal ROM while disabling access to any
other area. External pins serve as peripheral resources or general-purpose ports but not as bus pins.
■ Mode Setting
The FR family uses the mode pins (MD2 to MD0) and the mode data to set the operation mode.
●
Mode pins
Three mode pins MD2, MD1, and MD0 are used to specify a mode vector and reset vector fetch.
The mode pins must not be set to any combination of values other than listed in the table below:
Mode pins
MD2 MD1 MD0
0 0 0
Note:
MD2, MD1, MD0: The settings without 000B are prohibited.
62
Bus modes
Single chip
Mode name
Internal ROM mode vector
B
Reset vector
Remarks
access area
Internal