HD64F2149 Datasheet, PDF (692/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

22.1.2 Register Configuration
The chip on-chip ROM is controlled by the operating mode and register MDCR. The register
configuration is shown in table 22.1.
Table 22.1 ROM Register
Register Name
Mode control register
Abbreviation
MDCR
Note: * Lower 16 bits of the address.
R/W Initial Value
Address*
R/W Undefined
H'FFC5
Depends on the operating mode
22.2 Register Descriptions
22.2.1 Mode Control Register (MDCR)
Bit
7
6
5
4
3
2
1
0
EXPE
—
—
—
—
—
MDS1 MDS0
Initial value
—*
0
0
0
0
0
—*
—*
Read/Write R/W*
—
—
—
—
—
R
R
Note: * Determined by the MD1 and MD0 pins.
MDCR is an 8-bit read-only register used to set the chip operating mode and monitor the current
operating mode.
The EXPE bit is initialized in accordance with the mode pin states by a reset and in hardware
standby mode.
Bit 7—Expanded Mode Enable (EXPE): Sets expanded mode. In mode 1, EXPE is fixed at 1
and cannot be modified. In modes 2 and 3, EXPE has an initial value of 0 and can be read or
written.
Bit 7
EXPE
0
1
Description
Single-chip mode selected
Expanded mode selected
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