HD64F2145 Datasheet, PDF (103/829 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Section 3 MCU Operating Modes
3.1 MCU Operating Mode Selection
This LSI has three operating modes (modes 1 to 3). The operating mode is determined by the
setting of the mode pins (MD1 and MD0). Table 3.1 shows the MCU operating mode selection.
Table 3.1 lists the MCU operating modes.
Table 3.1 MCU Operating Mode Selection
MCU
Operating
Mode
0
1
2
3
MD1
0
1
MD0
0
1
0
1
CPU
Operating
Mode
—
Normal
Advanced
Normal
Description
On-Chip
ROM
—
—
Expanded mode with on-chip ROM disabled Disabled
Expanded mode with on-chip ROM enabled Enabled
Single-chip mode
Expanded mode with on-chip ROM enabled
Single-chip mode
Mode 1 is an expanded mode that allows access to external memory and peripheral devices. With
modes 2 and 3, operation begins in single-chip mode after reset release, but a transition can be
made to external expansion mode by setting the EXPE bit in MDCR to 1.
Mode 0 cannot be used in this LSI. Thus, mode pins should be set to enable mode 1, 2 or 3 in
normal program execution state. Mode pins should not be changed during operation.
3.2 Register Descriptions
The following registers are related to the operating mode. For details on the bus control register
(BCR), refer to section 6.3.1, Bus Control Register (BCR).
• Mode control register (MDCR)
• System control register (SYSCR)
• Serial timer control register (STCR)
Rev. 2.0, 08/02, page 63 of 788