H8S-2345 Datasheet, PDF (97/927 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer

3.3 Operating Mode Descriptions
Section 3 MCU Operating Modes
3.3.1 Mode 1 (ZTAT, Mask ROM, and ROMless Versions Only)
The CPU can access a 64-kbyte address space in normal mode. The on-chip ROM is disabled, and
8-bit bus mode is set, immediately after a reset.
Ports B and C function as an address bus, port D functions as a data bus, and part of port F carries
bus control signals. However, note that if 16-bit access is designated by the bus controller, the bus
mode switches to 16 bits and port E becomes a data bus.
3.3.2 Mode 2^*1 (ZTAT and Mask ROM Versions Only)
The CPU can access a 64-kbyte address space in normal mode. The on-chip ROM is enabled, and
8-bit bus mode is set. immediately after a reset.
Ports B and C function as input ports immediately after a reset. They can each be set to output
addresses by setting the corresponding bits in the data direction register (DDR) to 1. Port D
functions as a data bus, and part of port F carries bus control signals. However, note that if 16-bit
access is designated by the bus controller, the bus mode switches to 16 bits and port E becomes a
data bus.
The amount of on-chip ROM that can be used is limited to 56 kbytes.
3.3.3 Mode 3^*1 (ZTAT and Mask ROM Versions Only)
The CPU can access a 64-kbyte address space in normal mode. The on-chip ROM is enabled, but
external addresses cannot be accessed.
All I/O ports are available for use as input-output ports.
The amount of on-chip ROM that can be used is limited to 56 kbytes.
3.3.4 Mode 4^*2
The CPU can access a 16-Mbyte address space in advanced mode. The on-chip ROM is disabled.
Pins P1₃ to P1₀, ports A, B, and C function as an address bus, ports D and E function as a data bus,
and part of port F carries bus control signals. Pins P1₃ to P1₀ function as inputs immediately after a
reset. Each of these pins can be set to output addresses by setting the corresponding bit in the data
direction register (DDR) to 1.
Rev. 4.00 Feb 15, 2006 page 73 of 900
REJ09B0291-0400