HD64F3028F25 Datasheet, PDF (87/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection
The H8/3028 Group 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
Description
Operating
Mode Pins
Mode
MD2 MD1 MD0
Address Space
Initial Bus On-Chip On-Chip
Mode^*1 ROM
RAM
—
0
0
0
Mode 1 0
0
1
Mode 2 0
1
0
Mode 3 0
1
1
Mode 4 1
0
0
Mode 5 1
0
1
—
Expanded mode
Expanded mode
Expanded mode
Expanded mode
Expanded mode
—
8 bits
16 bits
8 bits
16 bits
8 bits
—
Disabled
Disabled
Disabled
Disabled
Enabled
—
Enabled^*2
Enabled^*2
Enabled^*2
Enabled^*2
Enabled^*2
Mode 6 1
1
0
Single-chip normal mode —
Enabled Enabled
Mode 7 1
1
1
Single-chip advanced
—
mode
Enabled Enabled
Notes: 1. In modes 1 to 5, 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 three choices: 64 kbytes, 1 Mbyte, or 16 Mbyte.The external
data bus is either 8 or 16 bits wide depending on ABWCR settings. If 8-bit access is selected for
all areas, 8-bit bus mode is used. 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.
Rev. 2.00, 09/03, page 55 of 890