HD6412350 Hitachi, HD6412350 Datasheet - Page 90

• Manufacturer Part Number: HD6412350
• Description: (HD6412350 / HD6432351) 16-BIT MICROCONTROLLER
• Manufacturer: Hitachi

The H8S/2350 can be used only in modes 1, 4, and 5. 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.
3.1.2
The H8S/2351 has seven operating modes (modes 1 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 (MD
Table 3-2 lists the MCU operating modes.
Table 3-2
MCU
Operating
Mode
0
1
2
3
4
5
6
7
The CPU's architecture allows for 4 Gbytes of address space, but the H8S/2351 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.
70
H8S/2351 Operating Mode Selection
MD
0
1
MCU Operating Mode Selection (H8S/2351)
2
MD
0
1
0
1
1
MD
0
1
0
1
0
1
0
1
2
0
to MD
CPU
Operating
Mode
—
Normal
Advanced On-chip ROM disabled, Disabled 16 bits
0
).
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
Enabled 8 bits
Initial
Width
—
—
8 bits
—
External Data Bus
Max.
Width
16 bits
16 bits
16 bits
16 bits
16 bits