MC9S12Q128_10 Datasheet, PDF (381/644 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 13 Serial Communications Interface (S12SCIV2) Block Description
13.1.4 Block Diagram
Figure 13-1 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 13-1. SCI Block Diagram
13.2 External Signal Description
The SCI module has a total of two external pins:
13.2.1 TXD-SCI Transmit Pin
This pin serves as transmit data output of SCI.
13.2.2 RXD-SCI Receive Pin
This pin serves as receive data input of the SCI.
TXDATA OUT
Freescale Semiconductor
MC9S12Q128
381
Rev 1.10