Modes 5 and 6 are externally expanded modes that enable access to external memory and
peripheral devices and also enable access to the on-chip ROM. Mode 5 supports a maximum
address space of 1 Mbyte. Mode 6 supports a maximum address space of 16 Mbytes.
Mode 7 is a single-chip mode that operates using the on-chip ROM, RAM, and registers, and
makes all I/O ports available. Mode 7 supports a 1-Mbyte address space.
The H8/3048 Series can be used only in modes 1 to 7. The inputs at the mode pins must select one
of these seven modes. The inputs at the mode pins must not be changed during operation.
3.1.2 Register Configuration
The H8/3048 Series has a mode control register (MDCR) that indicates the inputs at the mode pins
(MD
2
to MD
0
), and a system control register (SYSCR). Table 3-2 summarizes these registers.
Table 3-2 Registers
Address
*
Name
Abbreviation
R/W
Initial Value
H'FFF1
Mode control register
MDCR
R
Undetermined
H'FFF2
System control register
SYSCR
R/W
H'0B
Note:
*
The lower 16 bits of the address are indicated.
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