Datasheet

Section 3 MCU Operating Modes
Rev. 4.00 Sep 27, 2006 page 83 of 1130
REJ09B0327-0400
Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection
This LSI has three operating modes (modes 1 to 3). These modes enable selection of the CPU
operating mode and enabling/disabling of on-chip ROM, by setting the mode pins (MD1 and
MD0).
Table 3.1 lists the MCU operating modes.
Table 3.1 MCU Operating Mode Selection
MCU
Operating
Mode MD1 MD0
CPU
Operating
Mode Description
On-Chip
ROM
000—— —
1 1 Normal Expanded mode with on-chip ROM disabled Disabled
2 1 0 Advanced Expanded mode with on-chip ROM enabled
Single-chip mode
Enabled
3 1 Normal Expanded mode with on-chip ROM enabled
Single-chip mode
The CPU’s architecture allows for 4 Gbytes of address space, but this LSI actually access a
maximum of 16 Mbytes.
Mode 1 is an externally expanded mode that allows access to external memory and peripheral
devices. With modes 2 and 3, operation begins in single-chip mode after reset release, but a
transition can be made to external expansion mode by setting the EXPE bit in MDCR.
This LSI can only be used in modes 1 to 3. These means that the mode pins must select one of
these modes. Do not changes the inputs at the mode pins during operation.