HD6433044 Datasheet, PDF (70/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection
The H8/3048 Series has seven operating modes (modes 1 to 7) that are selected by the mode pins
(MD₂ to MD₀) as indicated in table 3-1. The input at these pins determines the size of the address
space and the initial bus mode.
Table 3-1 Operating Mode Selection
Operating
Mode
—
Mode Pins
MD₂ MD₁ MD₀
000
Address Space
—
Description
Initial Bus On-Chip
Mode^*1
ROM
—
—
On-Chip
RAM
—
Mode 1
001
Expanded mode
8 bits
Disabled Enabled^*2
Mode 2
010
Expanded mode
16 bits
Disabled Enabled^*2
Mode 3
011
Expanded mode
8 bits
Disabled Enabled^*2
Mode 4
100
Expanded mode
16 bits
Disabled Enabled^*2
Mode 5
101
Expanded mode
8 bits
Enabled Enabled^*2
Mode 6
110
Expanded mode
8 bits
Enabled Enabled^*2
Mode 7
111
Single-chip advanced —
mode
Enabled Enabled
Notes: 1. In modes 1 to 6, an 8-bit or 16-bit data bus can be selected on a per-area basis by
settings made in the area bus width control register (ABWCR). For details see
section 6, Bus Controller.
2. If the RAME bit in SYSCR is cleared to 0, these addresses become external addresses.
For the address space size there are two choices: 1 Mbyte or 16 Mbytes. The external data bus is
either 8 or 16 bits wide depending on ABWCR settings. If 8-bit access is selected for all areas, the
external data bus is 8 bits wide. For details see section 6, Bus Controller.
Modes 1 to 4 are externally expanded modes that enable access to external memory and peripheral
devices and disable access to the on-chip ROM. Modes 1 and 2 support a maximum address space
of 1 Mbyte. Modes 3 and 4 support a maximum address space of 16 Mbytes.
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