Datasheet

Section 3 MCU Operating Modes
Rev. 2.00 Sep. 28, 2009 Page 60 of 870
REJ09B0429-0200
3.3 Operating Mode Descriptions
3.3.1 Mode 2
The CPU can access a 16 Mbytes address space in advanced mode. The on-chip ROM is enabled.
After a reset, the LSI is set to single-chip mode. To access an external address space, bit EXPE in
MDCR should be set to 1.
• Normal extended mode
In extended modes, ports 1 and 2 function as input ports after a reset.
Ports 1 and 2 function as an address bus by setting 1 to the corresponding port data direction
register (DDR). Port 3 functions as a data bus port, and parts of port 9 carry bus control
signals. Port 6 functions as a data bus port when the ABW bit in WSCR is cleared to 0.
• Multiplex extended mode
When 8-bit bus is specified, port 2 functions as the port for address output and data
input/output regardless of the setting of the data direction register (DDR). Port 1 can be used as
a general port.
When 16-bit bus is specified, ports 1 and 2 function as the port for address output and data
input/output regardless of the setting of the data direction register (DDR).