
Chapter 2 Port Integration Module (S12XEPIMV1)
MC9S12XE-Family Reference Manual , Rev. 1.07
106
Freescale Semiconductor
2.3.10
Port D Data Direction Register (DDRD)
Table 2-9. DDRC Register Field Descriptions
Field
Description
7-0
DDRC
Port C Data Direction—
This register controls the data direction of pins 7 through 0.
The external bus function controls the data direction for the associated pins. In this case the data direction bits will
not change.
When operating a pin as a general purpose I/O, the associated data direction bit determines whether it is an input
or output.
1 Associated pin is configured as output.
0 Associated pin is configured as high-impedance input.
Address 0x0007 (PRR)
Access: User read/write
1
1
Read: Anytime. In emulation modes, read operations will return the data from the external bus, in all other modes the data
source is depending on the data direction value.
Write: Anytime. In emulation modes, write operations will also be directed to the external bus.
7
6
5
4
3
2
1
0
R
DDRD7
DDRD6
DDRD5
DDRD4
DDRD3
DDRD2
DDRD1
DDRD0
W
Reset
0
0
0
0
0
0
0
0
Figure 2-8. Port D Data Direction Register (DDRD)
Table 2-10. DDRD Register Field Descriptions
Field
Description
7-0
DDRD
Port D Data Direction
—
This register controls the data direction of pins 7 through 0.
When used with the external bus this function controls the data direction for the associated pins. In this case the data
direction bits will not change.
When operating a pin as a general purpose I/O, the associated data direction bit determines whether it is an input
or output.
1 Associated pin is configured as output.
0 Associated pin is configured as high-impedance input.