HD64F2149 Datasheet, PDF (109/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection
The H8S/2169 or H8S/2149 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
0
1
2
3
MD1 MD0
0
0
1
1
0
1
CPU
Operating
Mode
Description
On-Chip
ROM
—
—
—
Normal
Expanded mode with on-chip ROM disabled Disabled
Advanced Expanded mode with on-chip ROM enabled Enabled
Single-chip mode
Normal
Expanded mode with on-chip ROM enabled
Single-chip mode
The CPU’s architecture allows for 4 Gbytes of address space, but the H8S/2169 or H8S/2149
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.
The H8S/2169 or H8S/2149 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.
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