mc68hc908gr16 Freescale Semiconductor, Inc, mc68hc908gr16 Datasheet - Page 128

• Manufacturer Part Number: mc68hc908gr16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Input/Output Ports (PORTS)
12.4 Port C
Port C is a 7-bit, general-purpose bidirectional I/O port. Port C also has software configurable pullup
devices if configured as an input port.
12.4.1 Port C Data Register
The port C data register (PTC) contains a data latch for each of the port C pins.
PTC6 and PTC0 — Port C Data Bits
12.4.2 Data Direction Register C
Data direction register C (DDRC) determines whether each port C pin is an input or an output. Writing a 1
to a DDRC bit enables the output buffer for the corresponding port C pin; a 0 disables the output buffer.
DDRC6 and DDRC0 — Data Direction Register C Bits
Figure 12-11
128
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.
These read/write bits control port C data direction. Reset clears DDRC6 and DDRC0, configuring all
port C pins as inputs.
1 = Corresponding port C pin configured as output
0 = Corresponding port C pin configured as input
shows the port C I/O logic.
Address:
Address:
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.
Reset:
Reset:
Read:
Read:
Write:
Write:
$0002
$0006
Bit 7
Bit 7
0
0
0
Figure 12-10. Data Direction Register C (DDRC)
= Unimplemented
= Unimplemented
Figure 12-9. Port C Data Register (PTC)
DDRC6
PTC6
6
6
0
MC68HC908GR16 Data Sheet, Rev. 5.0
DDRC5
PTC5
5
5
0
NOTE
DDRC4
Unaffected by reset
PTC4
4
4
0
DDRC3
PTC3
R
3
3
0
= Reserved
DDRC2
PTC2
2
2
0
DDRC1
PTC1
1
1
0
Freescale Semiconductor
DDRC0
PTC0
Bit 0
Bit 0
0