521
Asynchronous Serial Interface (UARTA)
Chapter 16
Preliminary User’s Manual U17566EE1V2UM00
16.5.2
SBF transmission/reception format
The UARTA has an SBF (Sync Break Field) transmission/reception control
function to enable use of the LIN function.
About LIN
LIN stands for Local Interconnect Network and is a low-speed (1 to 20 kbps)
serial co
mmunication protocol intended to aid the cost reduction of an automotive
network.
LIN communication is single-master communication, and up to 15 slaves can
be connected to one master.
The LIN slaves are used to control the switches, actuators, and sensors, and
these are connected to the LIN master via the LIN network.
Normally, the LIN master is connected to a network such as CAN (Controller
Area Network).
In addition, the LIN bus uses a single-wire method and is connected to the
nodes via a transceiver that complies with ISO9141.
In the LIN protocol, the master transmits a frame with baud rate information
and the slave receives it and corrects the baud rate error. Therefore,
communication is possible when the baud rate error in the slave is
±
15% or
less.
Figure 16-2
and
Figure 16-3
outline the transmission and reception
manipulations of LIN.
Figure 16-2
LIN transmission manipulation outline
Note
1.
The interval between each field is controlled by software.
2.
SBF output is performed by hardware. The output width is the bit length set
by the UAnOPT0.UAnSBL2 to UAnOPT0.UAnSBL0 bits. If even finer
output width adjustments are required, such adjustments can be
performed using the UAnCTLn.UAnBRS7 to UAnCTLn.UAnBRS0 bits.
3.
80H transfer in the 8-bit mode is substituted for the wakeup signal frame.
S
leep
bus
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a
ke-
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p
s
ign
a
l
fr
a
me
S
ynch
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re
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S
ynch
field
Ident
field
DATA
field
DATA
field
Check
S
UM
field
INTUAnR
interr
u
pt
TXDAn (o
u
tp
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t)
Note
3
8
b
it
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Note 1
Note 2
1
3
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BF tr
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mi
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ion
Note 4
55H
tr
a
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ion
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