Specifications

SCI Communication Format
8-15 Serial Communications Interface (SCI)
Figure 8–7. SCI RX Signals in Communication Modes
RXENA
RXRDY
1
6
34
52
012345 012
Start Stop Start
Ad Pa
SCIRXD pin
Frame
Notes: 1) Flag bit RXENA (SCICTL1.0) goes high to enable the receiver.
2) Data arrives on the SCIRXD pin, start bit detected.
3) Data is shifted from RXSHF to the receive buffer register (SCIRXBUF); an interrupt is requested. Flag bit RXRDY
(SCIRXST.6) goes high to signal that a new character has been received.
4) The program reads SCIRXBUF; flag RXRDY is automatically cleared.
5) The next byte of data arrives on the SCIRXD pin; the start bit is detected, then cleared.
6) Bit RXENA is brought low to disable the receiver. Data continues to be assembled in RXSHF but is not transferred
to the receive buffer register.
8.4.2 Transmitter Signals in Communication Modes
Figure 8–8 illustrates an example of transmitter signal timing that assumes the
following conditions:
- Address-bit wake-up mode (address bit does not appear in idle-line mode)
- Three bits per character