MC908AP8CFBE Datasheet, PDF (168/324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Serial Communications Interface Module (SCI)
NOTE
The PTB2/TxD pin is an open-drain pin when configured as an output.
Therefore, when configured as a general purpose output pin (PTB2), a
pullup resistor must be connected to this pin.
11.7.2 RxD (Receive Data)
When the SCI is enabled (ENSCI=1), the PTB3/RxD pin becomes the serial data input, RxD, to the SCI
receiver regardless of the state of the DDRB3 bit in data direction register B (DDRB).
NOTE
The PTB3/RxD pin is an open-drain pin when configured as an output.
Therefore, when configured as a general purpose output pin (PTB3), a
pullup resistor must be connected to this pin.
11.8 I/O Registers
These I/O registers control and monitor SCI operation:
• SCI control register 1 (SCC1)
• SCI control register 2 (SCC2)
• SCI control register 3 (SCC3)
• SCI status register 1 (SCS1)
• SCI status register 2 (SCS2)
• SCI data register (SCDR)
• SCI baud rate register (SCBR)
MC68HC908AP Family Data Sheet, Rev. 4
168
Freescale Semiconductor