Datasheet

Section 3 MCU Operating Modes
Rev. 4.00 Jun 06, 2006 page 72 of 1004
REJ09B0301-0400
3.1.2 Register Configuration
The H8S/2138 Group and H8S/2134 Group have a mode control register (MDCR) that indicates
the inputs at the mode pins (MD1 and MD0), a system control register (SYSCR) and bus control
register (BCR) that control the operation of the MCU, and a serial timer control register (STCR)
that controls the operation of the supporting modules. Table 3.2 summarizes these registers.
Table 3.2 MCU Registers
Name Abbreviation R/W Initial Value Address
*
Mode control register MDCR R/W Undetermined H'FFC5
System control register SYSCR R/W H'09 H'FFC4
Bus control register BCR R/W H'D7 H'FFC6
Serial timer control register STCR R/W H'00 H'FFC3
Note: * Lower 16 bits of the address.
3.2 Register Descriptions
3.2.1 Mode Control Register (MDCR)
7
EXPE
—*
R/W
*
6
—
0
—
5
—
0
—
4
—
0
—
3
—
0
—
0
MDS0
—*
R
2
—
0
—
1
MDS1
—*
R
Note: * Determined by pins MD1 and MD0.
Bit
Initial value
Read/Write
MDCR is an 8-bit read-only register that indicates the operating mode setting and the current
operating mode of the MCU.
The EXPE bit is initialized in coordination with the mode pin states by a reset and in hardware
standby mode.