HD6432345 Datasheet, PDF (91/907 Pages) Hitachi Semiconductor – H8S/2345 F-ZTAT Hardware Manual

Table 3.2 MCU Operating Mode Selection
MCU
CPU
Operating
Operating
Mode
MD₂ MD₁ MD₀ Mode
Description
0
000—
—
External Data Bus
On-Chip Initial
ROM Width
Max.
Width
—
—
1
1 Normal On-chip ROM disabled, Disabled 8 bits
16 bits
expanded mode
2*
10
On-chip ROM enabled, Enabled 8 bits
expanded mode
16 bits
3*
1
Single-chip mode
—
4
1 0 0 Advanced On-chip ROM disabled, Disabled 16 bits 16 bits
expanded mode
5
1
8 bits
16 bits
6*
10
On-chip ROM enabled, Enabled 8 bits
expanded mode
16 bits
7*
1
Single-chip mode
—
Note: * Not used on ROMless version.
The CPU's architecture allows for 4 Gbytes of address space, but the H8S/2345 Series actually
accesses a maximum of 16 Mbytes.
Modes 1, 2, and 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.
Note that the functions of each pin depend on the operating mode.
The H8S/2345 Series can be used only in modes 1 to 7. This means that the mode pins must be
set to select one of these modes. Do not change the inputs at the mode pins during operation.
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