MC68HC908KX2 MOTOROLA [Motorola, Inc], MC68HC908KX2 Datasheet - Page 184

• Manufacturer Part Number: MC68HC908KX2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Serial Communications Interface Module (SCI)
14.5.1 Data Format
14.5.2 Transmitter
14.5.2.1 Character Length
14.5.2.2 Character Transmission
Technical Data
184
The SCI uses the standard non-return-to-zero mark/space data format
illustrated in
Figure 14-4
The transmitter can accommodate either 8-bit or 9-bit data. The state of
the M bit in SCI control register 1 (SCC1) determines character length.
When transmitting 9-bit data, bit T8 in SCI control register 3 (SCC3) is
the ninth bit (bit 8).
During an SCI transmission, the transmit shift register shifts a character
out to the TxD pin. The SCI data register (SCDR) is the write-only buffer
between the internal data bus and the transmit shift register. To initiate
an SCI transmission:
1. Enable the SCI by writing a logic 1 to the enable SCI bit (ENSCI)
2. Enable the transmitter by writing a logic 1 to the transmitter enable
START
START
BIT
BIT
Serial Communications Interface Module (SCI)
in SCI control register 1 (SCC1).
bit (TE) in SCI control register 2 (SCC2).
BIT 0
BIT 0
Figure
shows the structure of the SCI transmitter.
BIT 1
BIT 1
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
BIT 2
BIT 2
Figure 14-3. SCI Data Formats
14-3.
BIT 3
BIT 3
BIT M IN SCC1 CLEAR
8-BIT DATA FORMAT
9-BIT DATA FORMAT
BIT M IN SCC1 SET
BIT 4
BIT 4
BIT 5
BIT 5
BIT 6
BIT 6
OR DATA
PARITY
BIT 7
BIT 7
BIT
OR DATA
PARITY
STOP
BIT 8
BIT
BIT
START
STOP
NEXT
BIT
BIT
MOTOROLA
START
NEXT
BIT