Freescale Semiconductor, Inc.
Technical Data — MC68HC11P2
Section 5. Serial Communications Interface (SCI)
5.1 Contents
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
Data format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88
Transmit operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Receive operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89
Wakeup feature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91
SCI error detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
SCI registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93
Status flags and interrupts . . . . . . . . . . . . . . . . . . . . . . . . .101
5.10 Additional SCI subsystems . . . . . . . . . . . . . . . . . . . . . . . . .104
5.2 Introduction
The serial communications interface (SCI) is a universal asynchronous
receiver transmitter (UART). It has a non-return to zero (NRZ) format
(one start, eight or nine data, and one stop bit) that is compatible with
standard RS-232 systems.
The MC68HC11P2 contains three serial communications interfaces, all
having similar operation. For ease of reference, a full description of SCI1
(PD0/RXD1, PD1/TXD1) is given first, followed by summaries for SCI2
and SCI3, detailing their differences.
MC68HC11P2 — Rev 1.0
Technical Data
Serial Communications Interface (SCI)
For More Information On This Product,
Go to: www.freescale.com
FREESCALE [ Freescale ]
