H8S2633 Datasheet, PDF (159/1487 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 3 MCU Operating Modes
Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection
The H8S/2633 Group has four operating modes (modes 4 to 7). These modes enable selection of
the CPU operating mode, enabling/disabling of on-chip ROM, and the initial bus width setting, by
setting the mode pins (MD2 to MD0).
Table 3.1 lists the MCU operating modes.
Table 3.1 MCU Operating Mode Selection
MCU
CPU
Operating
Operating
Mode
MD2 MD1 MD0 Mode
Description
External Data Bus
On-Chip Initial
ROM Width
Max.
Width
0^*
000—
—
1^*
1
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
On-chip ROM enabled, Enabled 8 bits
16 bits
expanded mode
7
1
Single-chip mode
—
Note: * Not available in the H8S/2633 Group.
The CPU’s architecture allows for 4 Gbytes of address space, but the H8S/2633 Group actually
accesses a maximum of 16 Mbytes.
Modes 4 to 6 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.
Rev. 5.00 Mar 28, 2005 page 97 of 1422
REJ09B0234-0500