Datasheet

Section 3 MCU Operating Modes
Rev. 6.00 Mar. 18, 2010 Page 103 of 982
REJ09B0054-0600
Section 3 MCU Operating Modes
3.1 Operating Mode Selection
The LSI supports four operating modes (modes 7 to 4). These operating modes are used to switch
the pin functions. The operating mode is determined by the setting of the mode pins (MD2 to
MD0). Modes 6 to 4 are external extended modes used to access external memory or peripheral
devices. In the external extended modes each area can be specified as an 8-bit or 16-bit address
space using the bus controller after program execution starts. In addition, the 16-bit bus mode is
used if any of the areas is configured as 16-bit address space. The 8-bit bus mode is used if all
areas are configured as 8-bit address space.
Mode 7 does not use external address space. Do not change the mode pin setting during operation.
Table 3.1 MCU Operating Mode Selection
External Data Bus
MCU
Operating
Mode
MD2 MD1 MD0
CPU Operating
Mode
Description
On-chip
ROM
Initial Value
Maximum
Value
4 1 0 0 Advanced mode On-chip ROM
disabled, extended
mode
Disabled 16 bits 16 bits
5 1 0 1 Advanced mode On-chip ROM
disabled, extended
mode
Disabled 8 bits 16 bits
6 1 1 0 Advanced mode On-chip ROM
enabled, extended
mode
Enabled 8 bits 16 bits
7 1 1 1 Advanced mode Single-chip mode Enabled — —