Chapter 2 Port Integration Module (S12XEP100PIMV1)
MC9S12XE-Family Reference Manual , Rev. 1.19
146
Freescale Semiconductor
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.
2.3.56
Port H Reduced Drive Register (RDRH)
1
DDRH
Port H data direction
—
This register controls the data direction of pin 1.
The enabled SCI6 forces the I/O state to be an output. Depending on the configuration of the enabled routed SPI1
this pin will be forced to be input or output. In those cases the data direction bits will not change. The DDRM bits
revert to controlling the I/O direction of a pin when the associated peripheral module is disabled.
1 Associated pin is configured as output.
0 Associated pin is configured as input.
0
DDRH
Port H data direction
—
This register controls the data direction of pin 0.
The enabled SCI6 forces the I/O state to be an input. Depending on the configuration of the enabled routed SPI1
this pin will be forced to be input or output. In those cases the data direction bits will not change. The DDRM bits
revert to controlling the I/O direction of a pin when the associated peripheral module is disabled.
1 Associated pin is configured as output.
0 Associated pin is configured as input.
Address 0x0263
Access: User read/write
(1)
1. Read: Anytime.
Write: Anytime.
7
6
5
4
3
2
1
0
R
RDRH7
RDRH6
RDRH5
RDRH4
RDRH3
RDRH2
RDRH1
RDRH0
W
Reset
0
0
0
0
0
0
0
0
Figure 2-54. Port H Reduced Drive Register (RDRH)
Table 2-52. RDRH Register Field Descriptions
Field
Description
7-0
RDRH
Port H reduced drive
—Select reduced drive for outputs
This register configures the drive strength of output pins 7 through 0 as either full or reduced. If a pin is used as input
this bit has no effect.
1 Reduced drive selected (approx. 1/5 of the full drive strength).
0 Full drive strength enabled.
Table 2-51. DDRH Register Field Descriptions (continued)
Field
Description
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
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for
import
or
sale
in
the
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States
prior
to
September
2010:
S12XE
products
in
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packages