HD64F2638F20J Datasheet, PDF (129/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
Section 3 MCU Operating Modes
Section 3 MCU Operating Modes
3.1 Overview
3.1.1 Operating Mode Selection
The chip 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
0^*
000—
—
1^*
1—
2^*
10
3^*
1
4
1 0 0 Advanced On-chip ROM
5
1
disabled, expanded
mode
6
10
On-chip ROM
enabled, expanded
mode
7
1
Single-chip mode
Note: * Not available in the chip.
External Data Bus
On-Chip Initial
ROM Width
Max.
Width
—
—
—
Disabled 16 bits
8 bits
Enabled 8 bits
16 bits
16 bits
16 bits
—
—
The CPU’s architecture allows for 4 Gbytes of address space, but the chip 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.
REJ09B0103-0800 Rev. 8.00
May 28, 2010
Page 79 of 1458