MC68HC12 Datasheet, PDF (278/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

Multiple Serial Interface
16.3 Block diagram
RxD0
PS0
MSI
SCI0
TxD0
PS1
RxD1
PS2
SCI1
TxD1
PS3
MISO/SISO
MOSI/MOMI
SPI
SCK
CS/SS
PS4
PS5
PS6
PS7
HC12A4 MSI BLOCK
Figure 16-1. Multiple Serial Interface Block Diagram
16.4 Serial Communication Interface (SCI)
Two serial communication interfaces are available on the
MC68HC912DT128A. These are NRZ format (one start, eight or nine
data, and one stop bit) asynchronous communication systems with
independent internal baud rate generation circuitry and SCI transmitters
and receivers. They can be configured for eight or nine data bits (one of
which may be designated as a parity bit, odd or even). If enabled, parity
is generated in hardware for transmitted and received data. Receiver
parity errors are flagged in hardware. The baud rate generator is based
on a modulus counter, allowing flexibility in choosing baud rates. There
is a receiver wake-up feature, an idle line detect feature, a loop-back
mode, and various error detection features. Two port pins for each SCI
provide the external interface for the transmitted data (TXD) and the
received data (RXD).
For a faster wake-up out of WAIT mode by a received SCI message,
both SCI have the capability of sending a receiver interrupt, if enabled,
when RAF (receiver active flag) is set. For compatibility with other
M68HC12 products, this feature is active only in WAIT mode and is
disabled when VDDPLL supply is at V_SS level.
Technical Data
278
Multiple Serial Interface
MC68HC912DT128A — Rev 4.0
MOTOROLA