mc68hc908gp32 Freescale Semiconductor, Inc, mc68hc908gp32 Datasheet - Page 132

• Manufacturer Part Number: mc68hc908gp32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface Module (SCI)
SCI I/O (input/output) lines are implemented by sharing parallel I/O port pins. The full name of an SCI
input or output reflects the name of the shared port pin.
Table 13-1
shows the full names and the generic
names of the SCI I/O pins.
The generic pin names appear in the text of this section.
Table 13-1. Pin Name Conventions
Generic Pin Names:
RxD
TxD
Full Pin Names:
PTE1/RxD
PTE0/TxD
13.4 Functional Description
Figure 13-1
shows the structure of the SCI module. The SCI allows full-duplex, asynchronous, NRZ serial
communication among the MCU and remote devices, including other MCUs. The transmitter and receiver
of the SCI operate independently, although they use the same baud rate generator. During normal
operation, the CPU monitors the status of the SCI, writes the data to be transmitted, and processes
received data.
The baud rate clock source for the SCI can be selected via the configuration bit, SCIBDSRC, of the
CONFIG2 register ($001E). Source selection values are shown in
Figure
13-1.
MC68HC908GP32 Data Sheet, Rev. 10
132
Freescale Semiconductor