MC68HC908QC16_07 Datasheet, PDF (112/274 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output Ports (PORTS)
Table 11-2. Port B Pin Functions
PTBPUE
Bit
1
0
X
DDRB
Bit
0
0
1
PTB
Bit
X⁽¹⁾
X
X
I/O Pin
Mode
Input, V_DD(2)
Input, Hi-Z⁽⁴⁾
Output
Accesses to DDRB
Read/Write
DDRB7–DDRB0
DDRB7–DDRB0
DDRB7–DDRB0
1. X = don’t care
2. I/O pin pulled to V_DD by internal pullup.
3. Writing affects data register, but does not affect input.
4. Hi-Z = high impedance
Accesses to PTB
Read
Write
Pin
PTB7–PTB0⁽³⁾
Pin
PTB7–PTB0⁽³⁾
PTB7–PTB0
PTB7–PTB0
11.5 Port C
Port C is an 4-bit general purpose port. PTC3 is an input only port pin, while PTC2–PTC0 can be
configured for either input or output. Each port C pin can be configured to have an internal pullup when
used as an input pin.
NOTE
PTC3 has a high voltage detector to enable entry into special modes. Do
not exceed the V_DD level on this pin in normal operation.
11.5.1 Port C Data Register
The port C data register (PTC) contains a data latch for each of the port C pins.
Bit 7
Read: 0
Write:
Reset:
6
5
0
0
= Unimplemented
4
3
0
PTC3
Unaffected by reset
2
PTC2
1
PTC1
Bit 0
PTC0
Figure 11-9. Port C Data Register (PTC)
PTC[2:0] — 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.
PTC3 — Port C Data Bit
This read-only bit reads the state of the PTC3 pin.
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 3
112
Freescale Semiconductor