Datasheet

Serial Communications Interface Module (SCI)
MC68HC812A4 Data Sheet, Rev. 7
176 Freescale Semiconductor
14.10 Interrupt Sources
14.11 General-Purpose I/O Ports
Port S shares its pins with the multiple serial interface (MSI). In all modes, port S pins PS7–PS0 are
available for either general-purpose I/O or for SCI and SPI functions. See Chapter 13 Multiple Serial
Interface (MSI).
14.12 Serial Character Transmission Using the SCI
Code is intended to use SCI1 to serially transmit characters using polling to the LCD display on the
UDLP1 board: when the transmission data register is empty a flag will get set, which is telling us that
SC1DR is ready so we can write another byte. The transmission is performed at a baud rate of 9600.
Since the SCI1 is only being used for transmit data, the data register will not be used bidirectionally for
received data.
14.12.1 Equipment
For this exercise, use the M68HC812A4EVB emulation board.
Table 14-8. SCI Interrupt Sources
Interrupt
Source
Flag
Local
Enable
CCR
Mask
Vector
Address
SCI0 SCI1
Transmit data register empty TDRE TIE I bit
$FFD6,
$FFD7
$FFD4,
$FFD5
Transmission complete TC TCIE I bit
Receive data register full RDRF
RIE I bit
Receiver overrun OR
Receiver idle IDLE ILIE I bit