MC68HC908GR8 Datasheet, PDF (150/286 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Input/Output Ports (I/O)
Table 16-3. Port B Pin Functions
DDRB Bit
PTB Bit
I/O Pin Mode
Accesses to DDRB
Read/Write
0
X⁽¹⁾
Input, Hi-Z⁽²⁾
DDRB5–DDRB0
1
X
Output
DDRB5–DDRB0
Notes:
1. X = Don’t care
2. Hi-Z = High impedance
3. Writing affects data register, but does not affect input.
Accesses to PTB
Read
Write
Pin
PTB5–PTB0⁽³⁾
PTB5–PTB0
PTB5–PTB0
16.4 Port C
Port C is a 2-bit, general-purpose bidirectional I/O port. Port C also has software configurable pullup
devices if configured as an input port.
16.4.1 Port C Data Register
The port C data register (PTC) contains a data latch for each of the two port C pins.
Address: $0002
Bit 7
6
5
4
3
2
1
Bit 0
Read: 0
0
0
0
0
0
PTC1
PTC0
Write:
Reset:
Unaffected by reset
= Unimplemented
Figure 16-9. Port C Data Register (PTC)
PTC1–PTC0 — 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.
NOTE
PTC is not available in a 28-pin DIP and SOIC package
16.4.2 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.
Address:
Read:
Write:
Reset:
$0006
Bit 7
6
5
4
3
2
1
0
0
0
0
0
0
DDRC1
0
0
0
0
0
0
0
= Unimplemented
Figure 16-10. Data Direction Register C (DDRC)
Bit 0
DDRC0
0
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
150
Freescale Semiconductor