Input/Output (I/O) Ports (PORTS)
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
106 Freescale Semiconductor
10.4 Port C
Port C is a 7-bit, general-purpose, bidirectional I/O port that shares two of its pins with the analog-to-digital
convertor module (ADC).

10.4.1 Port C Data Register

The port C data register (PTC) contains a data latch for each of the seven port C pins.
PTC[6:0] — Port C Data Bits
These read/write bits are software-programmable. Data direction of each port C pin is under the control
of the corresponding bit in data direction register C. Reset has no effect on port C data.

10.4.2 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.
DDRC[6:0] — Data Direction Register C Bits
These read/write bits control port C data direction. Reset clears DDRC[6:0], 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.
Address: $0002
Bit 7654321Bit 0
Read: 0
PTC6 PTC5 PTC4 PTC3 PTC2 PTC1 PTC0
Write: R
Reset: Unaffected by reset
R= Reserved
Figure 10-8. Port C Data Register (PTC)
Address: $0006
Bit 7654321Bit 0
Read: 0
DDRC6 DDRC5 DDRC4 DDRC3 DDRC2 DDRC1 DDRC0
Write: R
Reset:00000000
R= Reserved
Figure 10-9. Data Direction Register C (DDRC)