Motorola MPC533 Reference Manual page 607

Chapter 15
Queued Serial Multi-Channel Module
The MPC533 contains one queued serial multi-channel module (QSMCM). The QSMCM
provides three serial communication interfaces: the queued serial peripheral interface
(QSPI) and two serial communications interfaces (SCI/UART). These submodules
communicate with the CPU via a common slave bus interface unit (SBIU).
The QSPI is a full-duplex, synchronous serial interface for communicating with peripherals
and other MCUs. It is enhanced from the original SPI in the QSMCM (queued serial
module) to include a total of 160 bytes of queue RAM to accommodate more receive,
transmit, and control information.
The duplicate, independent SCIs are full-duplex universal asynchronous receiver
transmitter (UART) serial interface. The original QSM SCI is enhanced by the addition of
an SCI, a common external baud clock source, receive and transmit buffers on one SCI. The
SCIs are fully compatible with the SCI systems found on other Motorola MCUs. The dual,
independent SCI, DSCI, submodule is used to communicate with external devices and other
MCUs via an asynchronous serial bus. The DSCI has all of the capabilities of previous SCI
systems as well as several significant new features. The following paragraphs describe the
features, pins, programmer's model (memory map), registers, and the transmit and receive
operations of the DSCI.
The SBIU provides an interface between the QSMCM module and the intermodule bus
(IMB3).
15.1 Block Diagram
Figure 15-1 shows the major components of the QSMCM.
MOTOROLA Chapter 15. Queued Serial Multi-Channel Module 15-1
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE