MC3S12RG128 Datasheet, PDF (445/546 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 16 Serial Communications Interface (SCIV2) Block Description
16.1.4 Block Diagram
Figure 16-1 is a high level block diagram of the SCI module, showing the interaction of various functional
blocks.
RX DATA IN
BUS CLOCK
SCI DATA REGISTER
RECEIVE SHIFT REGISTER
RECEIVE & WAKE UP CONTROL
BAUD
GENERATOR
÷16
DATA FORMAT CONTROL
TRANSMIT CONTROL
TRANSMIT SHIFT REGISTER
SCI DATA REGISTER
IDLE IRQ
RDR/OR IRQ
TDRE IRQ
TC IRQ
IRQ
TO CPU
Figure 16-1. SCI Block Diagram
16.2 External Signal Description
The SCI module has a total of two external pins:
16.2.1 TXD-SCI Transmit Pin
This pin serves as transmit data output of SCI.
16.2.2 RXD-SCI Receive Pin
This pin serves as receive data input of the SCI.
TXDATA OUT
MC3S12RG128 Data Sheet, Rev. 1.05
Freescale Semiconductor
445