mc68hc908kx8 Freescale Semiconductor, Inc, mc68hc908kx8 Datasheet - Page 113

• Manufacturer Part Number: mc68hc908kx8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

12.3 Pin Name Conventions
The generic names of the SCI input/output (I/O) pins are:
SCI I/O 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.
SCI I/O pins.The generic pin names appear in the text of this section.
12.4 Functional Description
Figure 12-3
communication between 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.
The source of the baud rate clock is determined by the configuration register 2 bit, SCIBDSRC. If
SCIBDSRC is set then the source of the SCI is the internal data bus clock. If SCIBDSRC is cleared, the
source of the SCI is oscillator output CGMXCLK.
During normal operation, the CPU monitors the status of the SCI, writes the data to be transmitted, and
processes received data.
12.4.1 Data Format
The SCI uses the standard non-return-to-zero mark/space data format illustrated in
Freescale Semiconductor
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•
RxD, receive data
TxD, transmit data
shows the structure of the SCI module. The SCI allows full-duplex, asynchronous, NRZ serial
START
START
BIT
BIT
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 Data Sheet, Rev. 2.1
BIT 0
BIT 0
Full Pin Names
BIT 1
BIT 1
Generic Pin
Table 12-1. Pin Name Conventions
BIT 2
BIT 2
Names
Figure 12-2. SCI Data Formats
BIT 3
BIT 3
Table 12-1
BIT M IN SCC1 CLEAR
8-BIT DATA FORMAT
9-BIT DATA FORMAT
BIT M IN SCC1 SET
BIT 4
BIT 4
PTB4/RxD
RxD
BIT 5
BIT 5
shows the full names and the generic names of the
BIT 6
BIT 6
OR DATA
PARITY
BIT 7
BIT 7
BIT
PTB5/TxD
OR DATA
PARITY
STOP
BIT 8
BIT
BIT
TxD
START
STOP
NEXT
BIT
BIT
START
NEXT
BIT
Pin Name Conventions
Figure
12-2.
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