HD6433308 HITACHI [Hitachi Semiconductor], HD6433308 Datasheet - Page 38

• Manufacturer Part Number: HD6433308
• Description: Hitachi Single-Chip MicroComputer
• Manufacturer: HITACHI [Hitachi Semiconductor]

2.4 Mode and System Control Registers (MDCR and SYSCR)
Two of the control registers in the register field are the mode control register (MDCR) and system
control register (SYSCR). The mode control register controls the MCU mode: the operating mode
of the H8/330 chip. The system control register has bits that enable or disable the on-chip RAM
and dual-port RAM. Table 2-2 lists the attributes of these registers.
Table 2-2. Mode and System Control Registers
Name
Mode control register
System control register
2.4.1 Mode Control Register (MDCR) – H’FFC5
Bit
Initial value
Read/Write
*
Bits 7 to 5 and 2—Reserved: These bits cannot be modified and are always read as “1.”
Bits 4 and 3—Reserved: These bits cannot be modified and are always read as “0.”
Bits 1 and 0—Mode Select 1 and 0 (MDS1 and MDS0): These bits indicate the values of the
mode pins (MD1 and MD0) latched on the rising edge of the RES signal. These bits can be read but
not written.
Coding example: To test whether the MCU is operating in mode 1:
The comparison is with H’E5 instead of H’01 because bits 7, 6, 5, and 2 are always read as “1.”
Initialized according to MD1 and MD0 inputs.
MOV.B @H’FFC5, R0L
CMP.B #H’E5, R0L
—
—
7
1
—
—
6
1
Abbreviation
MDCR
SYSCR
—
—
5
1
21
—
—
4
0
Read/Write
R
R/W
—
—
3
0
—
—
2
1
Address
H’FFC5
H’FFC4
MDS1
R
1
*
MDS0
R
0
*