Input/Output (I/O) Ports
Port C
MC68HC908GP32
•
MC68HC08GP32
—
Rev. 6
Technical Data
MOTOROLA
Input/Output (I/O) Ports
223
16.5.2 Data Direction Register C
Data direction register C (DDRC) determines whether each port C pin is
an input or an output. Writing a logic 1 to a DDRC bit enables the output
buffer for the corresponding port C pin; a logic 0 disables the output
buffer.
DDRC6–DDRC0 — Data Direction Register C Bits
These read/write bits control port C data direction. Reset clears
DDRC6–DDRC0, configuring all port C pins as inputs.
1 = Corresponding port C pin configured as output
0 = Corresponding port C pin configured as input
NOTE:
Avoid glitches on port C pins by writing to the port C data register before
changing data direction register C bits from 0 to 1.
Figure 16-11
shows the port C I/O logic.
NOTE:
For those devices packaged in a 40-pin dual in-line package and 42-pin
shrink dual in-line package, PTC5 and PTC6 are connected to ground
internally. DDRC5 and DDRC6 should be set to a 0 to configure PTC5
and PTC6 as inputs.
Address:
$0006
Bit 7
6
5
4
3
2
1
Bit 0
Read:
0
DDRC6
DDRC5
DDRC4
DDRC3
DDRC2
DDRC1
DDRC0
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 16-10. Data Direction Register C (DDRC)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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