HD6432351 Datasheet, PDF (89/989 Pages) Renesas Technology Corp – The H8S/2000 CPU has an internal 32-bit architecture, is provided with sixteen 16-bit general registers and a concise

Section 3 MCU Operating Modes
3.1 Overview
3.1.1 H8S/2350 Operating Mode Selection
The H8S/2350 has three operating modes (modes 1, 4, and 5). These modes are determined by the
mode pin (MD₂ to MD₀) settings. The CPU operating mode and initial bus width can be selected
as shown in table 3-1.
Table 3-1 lists the MCU operating modes.
Table 3-1 MCU Operating Mode Selection (H8S/2350)
MCU
CPU
Operating
Operating
Mode
MD₂ MD₁ MD₀ Mode
Description
0
000—
—
External Data Bus
On-Chip Initial
ROM Width
Max.
Width
—
—
1
1 Normal On-chip ROM disabled, Disabled 8 bits
16 bits
expanded mode
2
10—
—
—
—
—
3
1
4
1 0 0 Advanced On-chip ROM disabled, Disabled 16 bits 16 bits
5
1
expanded mode
8 bits
16 bits
6
10—
—
—
—
—
7
1
The CPU's architecture allows for 4 Gbytes of address space, but the H8S/2350 actually accesses a
maximum of 16 Mbytes.
Modes 1, 4, and 5 are externally expanded modes that allow access to external memory and
peripheral devices.
The external expansion modes allow switching between 8-bit and 16-bit bus modes. After program
execution starts, an 8-bit or 16-bit address space can be set for each area, depending on the bus
controller setting. If 16-bit access is selected for any one area, 16-bit bus mode is set; if 8-bit
access is selected for all areas, 8-bit bus mode is set.
Note that the functions of each pin depend on the operating mode.
69