mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 254

• Manufacturer Part Number: mc68hc908sr12
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface (SCI)
16.4 Pin Name Conventions
16.5 Functional Description
Data Sheet
254
NOTE:
The generic names of the SCI I/O pins are:
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.
of the SCI I/O pins. The generic pin names appear in the text of this
section.
When the SCI is enabled, the TxD pin is an open-drain output and
requires a pullup resistor to be connected for proper SCI operation.
Figure 16-1
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 ($001D). Source
selection values are shown in
•
•
RxD (receive data)
TxD (transmit data)
Serial Communications Interface (SCI)
Generic Pin Names:
Full Pin Names:
shows the structure of the SCI module. The SCI allows full-
Table 16-1
Table 16-1. Pin Name Conventions
shows the full names and the generic names
Figure
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
16-1.
PTB3/SCL1/RxD
RxD
Freescale Semiconductor
PTB2/SDA1/TxD
TxD