Chapter 4 Port Integration Module (S12XDP512PIMV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 239
4.3.2.48 Port H Data Direction Register (DDRH)
Read: Anytime.
Write: Anytime.
This register configures each port H pin as either input or output.
If the associated SCI channel or routed SPI module is enabled this register has no effect on the pins.
The SCI forces the I/O state to be an output for each port line associated with an enabled output (TXD5,
TXD4). It also forces the I/O state to be an input for each port line associated with an enabled input (RXD5,
RXD4). In those cases the data direction bits will not change.
If a SPI module is enabled, the SPI determines the pin direction. Refer to SPI section for details.
The DDRH bits revert to controlling the I/O direction of a pin when the associated peripheral modules are
disabled.
0x0262
76543210
R
DDRH7 DDRH6 DDRH5 DDRH4 DDRH3 DDRH2 DDRH1 DDRH0
W
Reset 00000000
Figure 4-50. Port H Data Direction Register (DDRH)
Table 4-45. DDRH Field Descriptions
Field Description
7–0
DDRH[7:0]
Data Direction Port H
0 Associated pin is configured as input.
1 Associated pin is configured as output.
Note: Due to internal synchronization circuits, it can take up to 2 bus clock cycles until the correct value is read
on PTH or PTIH registers, when changing the DDRH register.