HD6412340 HITACHI [Hitachi Semiconductor], HD6412340 Datasheet - Page 91

• Manufacturer Part Number: HD6412340
• Description: H8S/2345 F-ZTAT Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

Table 3.2
MCU
Operating
Mode
0
1
2*
3*
4
5
6*
7*
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.
MD
0
1
MCU Operating Mode Selection
2
MD
0
1
0
1
1
MD
0
1
0
1
0
1
0
1
0
CPU
Operating
Mode
—
Normal
Advanced On-chip ROM disabled,
Description
—
On-chip ROM disabled,
expanded mode
On-chip ROM enabled,
expanded mode
Single-chip mode
expanded mode
On-chip ROM enabled,
expanded mode
Single-chip mode
On-Chip
ROM
—
Disabled 8 bits
Enabled 8 bits
Disabled 16 bits
Enabled 8 bits
Initial
Width
—
—
8 bits
—
External Data Bus
Max.
Width
16 bits
16 bits
16 bits
16 bits
16 bits
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