Register Configuration; Register Descriptions; Mode Control Register (Mdcr) - Hitachi H8S/2646 Hardware Manual

The H8S/2646 Series can be used only in modes 4 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.
3.1.2

Register Configuration

The H8S/2646 Series has a mode control register (MDCR) that indicates the inputs at the mode
pins (MD2 to MD0), and a system control register (SYSCR) that controls the operation of the
H8S/2646 Series. Table 3-2 summarizes these registers.
Table 3-2 MCU Registers
Name
Mode control register
System control register
Pin function control register
Note: * Lower 16 bits of the address.
3.2

Register Descriptions

3.2.1

Mode Control Register (MDCR)

Bit : 7
—
Initial value : 1
R/W : —
Note: * Determined by pins MD2 to MD0.
MDCR is an 8-bit read-only register that indicates the current operating mode of the H8S/2646
Series.
Bit 7—Reserved: Cannot be written to.
Bits 6 to 3—Reserved: These bits are always read as 0 and cannot be written to.
Bits 2 to 0—Mode Select 2 to 0 (MDS2 to MDS0): These bits indicate the input levels at pins
MD2 to MD0 (the current operating mode). Bits MDS2 to MDS0 correspond to MD2 to MD0.
MDS2 to MDS0 are read-only bits, and they cannot be written to. The mode pin (MD2 to MD0)
input levels are latched into these bits when MDCR is read. These latches are cancelled by a reset.
80
Abbreviation R/W
MDCR R
SYSCR R/W
PFCR R/W
6 5 4
— — —
0 0 0
— — —
Initial Value
Undetermined
H'01
H'0D/H'00
3 2 1
— MDS2 MDS1
0 —* —*
— R R
Address*
H'FDE7
H'FDE5
H'FDEB
0
MDS0
—*
R