MC68332ACEH20 Datasheet, PDF (64/88 Pages) Freescale Semiconductor, Inc – 32-Bit Modular Microcontroller

Freescale Semiconductor, Inc.
6 Queued Serial Module
The QSM contains two serial interfaces, the queued serial peripheral interface (QSPI) and the serial
communication interface (SCI).
QSPI
IMB
INTERFACE
LOGIC
SCI
PORT QS
MISO/PQS0
MOSI/PQS1
SCK/PQS2
PCS0/SS/PQS3
PCS1/PQS4
PCS2/PQS5
PCS3/PQS6
TXD/PQS7
RXD
QSM BLOCK
Figure 13 QSM Block Diagram
6.1 Overview
The QSPI provides easy peripheral expansion or interprocessor communication through a full-duplex,
synchronous, three-line bus: data in, data out, and a serial clock. Four programmable peripheral chip-
select pins provide addressability for up to 16 peripheral devices. A self-contained RAM queue allows
up to 16 serial transfers of 8 to 16 bits each, or transmission of a 256-bit data stream without CPU in-
tervention. A special wraparound mode supports continuous sampling of a serial peripheral, with auto-
matic QSPI RAM updating, which makes the interface to A/D converters more efficient.
The SCI provides a standard nonreturn to zero (NRZ) mark/space format. It operates in either full- or
half-duplex mode. There are separate transmitter and receiver enable bits and dual data buffers. A
modulus-type baud rate generator provides rates from 64 to 524 kbaud with a 16.78-MHz system clock,
or 110 to 655 kbaud with a 20.97-MHz system clock. Word length of either 8 or 9 bits is software select-
able. Optional parity generation and detection provide either even or odd parity check capability. Ad-
vanced error detection circuitry catches glitches of up to 1/16 of a bit time in duration. Wakeup functions
allow the CPU to run uninterrupted until meaningful data is available.
An address map of the QSM is shown below.
MOTOROLA
64
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MC68332
MC68332TS/D