MC68HC812A4 Datasheet, PDF (101/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Bus Control and Input/Output (I/O)
Registers
6.4.8 Port D Data Direction Register
Address: $0007
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 6-8. Port D Data Direction Register (DDRD)
Read: Anytime, if register is in the map
Write: Anytime, if register is in the map
When port D is operating as a general-purpose I/O port, this register
determines the primary direction for each port D pin.
1 = Associated pin is an output.
0 = Associated pin is a high-impedance input.
This register is not in the map in wide expanded and peripheral modes.
Also, in special narrow expanded mode, the function of this port is
determined by the EMD control bit. If EMD is set, this register is not in
the on-chip map and port D is used for DATA7–DATA0 of visible internal
accesses. If EMD is clear, this port serves as general-purpose I/O or key
wakeup signals.
Advance Information
MOTOROLA
Bus Control and Input/Output (I/O)
MC68HC812A4 — Rev. 3.0
101