M68HC16 Z SERIES
QUEUED SERIAL MODULE
USER’S MANUAL
9-1
SECTION 9
QUEUED SERIAL MODULE
This section is an overview of the queued serial module (QSM). Refer to the
QSM Ref-
erence Manual (QSMRM/AD) for complete information about the QSM.
9.1 General
The QSM contains two serial interfaces: the queued serial peripheral interface (QSPI)
and the serial communication interface (SCI).
is a block diagram of the
QSM. The QSM is present on the MC68HC16Z1, MC68CK16Z1, MC68CM16Z1,
MC68HC16Z2, and MC68HC16Z3 microcontrollers.
Figure 9-1 QSM Block Diagram
The QSPI provides peripheral expansion or interprocessor communication through a
full-duplex, synchronous, three-line bus. Four programmable peripheral chip-selects
can select up to sixteen peripheral devices by using an external 1 of 16 line selector.
A self-contained RAM queue allows up to sixteen serial transfers of eight to sixteen
bits each or continuous transmission of up to a 256-bit data stream without CPU16 in-
tervention. A special wrap-around mode supports continuous transmission/reception
of data.
QSPI
INTERFACE
LOGIC
SCI
MISO/PQS0
MOSI/PQS1
SCK/PQS2
PCS0/SS/PQS3
PCS1/PQS4
PCS2/PQS5
PCS3/PQS6
TXD/PQS7
RXD
PORT QS
QSM BLOCK
IMB
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..