MC908JB12DWE Datasheet, PDF (269/332 Pages) Freescale Semiconductor, Inc – MC68HC908JB16 Technical Data

Input/Output (I/O) Ports
14.4 Port C
Port C is a 2-bit special function port that shares its pins with the serial
communications interface (SCI) module. These pins have software
configurable pullups.
14.4.1 Port C Data Register
The port C data register contains a data latch for each of the two
port C pins.
Address: $0002
Bit 7
6
Read: 0
0
Write:
Reset:
5
4
3
2
0
0
0
0
Unaffected by reset
1
Bit 0
PTC1 PTC0
Alternative
Function:
Additional
Function:
RxD
TxD
Optional Optional
pullup pullup
Figure 14-5. Port C Data Register (PTC)
PTC[1:0] — 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.
The port C pullup enable bit, PCP, in the port option control register
(POCR) enables pullups on PTC[1:0] if the respective pin is
configured as an input. (See 14.7 Port Options.)
TxD, RxD — SCI Data I/O Pins
The TxD and RxD pins are the transmit data output and receive data
input for the SCI module. The SCI enable bit, ENSCI, in the SCI
control register 1 enables the PTC0/TxD and PTC1/RxD pins as SCI
TxD and RxD pins and overrides any control from the port I/O. See
Section 12. Serial Communications Interface Module (SCI).
MC68HC908JB16 — Rev. 1.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
269