Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
7. Operation of LIN Interface (v2.1)
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
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Slave Operations
Selecting Slave Operation
To make the LIN interface (v2.1) work as the slave device, set the SCR:MS bit to "1".
From LIN Break Field Reception to Synch Field Reception
There are two methods that it is confirmed whether the automatic baud rate adjustment was executed in
from LIN Break Field reception to Synch Field reception.
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Method of comparing BGR with STMR
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Method of confirming SACSR:BST bit
Processing using these methods is as follows.
1. Method of comparing BGR with STMR
(1) The automatic baud rate adjustment is set to effective (SACSR:AUTE=1).
(2) When LIN Break Field is input, LIN Break Field is detected in the 11th bit (SSR:LBD=1). At this time,
if the ESCR:LBIE bit is set in "1", the status interrupt is generated. After LIN Break Field is detected
(SSR:LBD=1), the serial timer is set to prohibition (SACSR:TMRE=0).
(3) When LIN interface (v2.1) detects the first falling edge of Sync Field, serial timer register (STMR) is
initialized to "0".
(4) When the fifth falling edge of Sync Field is detected, Sync Field detection flag (SACSR:SFD) is set in
"1". At this time, the following are confirmed and the presence of the automatic baud rate adjustment is
confirmed.
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The reading value of baud rate generator register (BGR) becomes equal with serial timer register
(STMR) at Sync Field detection (SACSR:SFD=1) when the automatic baud rate is adjusted.
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The reading value of baud rate generator register (BGR) is different from serial timer register
(STMR) at Sync Field detection (SACSR:SFD=1) when the automatic baud rate adjustment is not
adjusted.
2. Method of using SACSR:BST bit
(1) The automatic baud rate adjustment is set to effective (SACSR:AUTE=1).
(2) When LIN Break field is input, LIN Break field will be detected (SSR:LBD=1) at eleventh bit.
At this time, when ESCR:LBIE bit is set to "1", the reception interrupt will be generated.
(3) When the first falling edge of Sync field is detected by the LIN interface (v2.1), serial timer register
(STMR) will be initialized to "0".
(4) When fifth falling edge of Sync field is detected, Sync field detection flag (SACSR:SFD) will be set to
"1".
(5) When fifth falling edge of Sync field is detected, operation will be performed as follows depending on
the serial timer register (STMR).
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When the values set in the serial timer register (STMR) is the values set in the sync field lower limit
register (SFLR) or larger and is the values set in the sync field upper limit register (SFUR) or smaller, the
values set in the serial timer register (SMTR) will be set to the baud rate generator register (BGR) and
the baud rate setting flag (SACSR:BST) will be set to "1".
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When the values set in the serial timer register (STMR) is smaller than the values set in the sync field
lower limit register (SFLR) or larger than the values set in the sync field upper limit register (SFUR), the
values set in the baud rate generator register (BGR) will not be changed and the baud rate setting flag
(SACSR:BST) will be reset to "0".
MB91520 Series
MN705-00010-1v0-E
1599