Bus Modes - Fujitsu FR60 Hardware Manual

3.8.1

Bus Modes

FR family microcontrollers have the three types of bus modes listed below.
For details, see Section "3.1 Memory Space".
■ Bus Mode 0 (Single-chip Mode)
In this mode, internal I/O, D-bus RAM, F-bus RAM, and F-bus ROM are valid. Access to other areas is
invalid.
External pins do not serve as bus pins, but serve as peripheral or general-purpose ports.
■ Bus Mode 1 (Internal-ROM/External-bus Mode)
In this mode, internal I/O, D-bus RAM, and F-bus RAM, as well as F-bus ROM, are valid. Access to an
area that enables external access is handled as access to an external space. Some external pins serve as bus
pins.
■ Bus Mode 2 (External-ROM/External-bus Mode)
In this mode, internal I/O and D-bus RAM are valid, but access to F-bus RAM and F-bus ROM are invalid.
All accesses are handled as access to an external space. Some external pins serve as bus pins.
91