Fujitsu FR81S Benutzerhandbuch
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
7. Operation of LIN Interface (v2.1)
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
282
From ID Field Transmission to Data Field Transmission/Reception
Specify whether to transmit the Data Field to the slave device or receive it.
⋅
In the case of Data Field transmission:
⋅
When the first bit of the ID Field is transmitted, the SSR:TDRE bit is set to "1". Data can then be written
in the Data Field.
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In the case of Data Field reception:
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When the first bit of the ID Field is transmitted, the SSR:TDRE bit is set to "1". However, do not write
transmission data.
Also, disable transmission interrupts (SCR:TIE=0).
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When the Data Field is received, the SSR:RDRF bit is set to "1". If reception interrupts are enabled
(SCR:RIE=1) at this time, a reception interrupt will occur.
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The start bit is detected when the falling edge is detected after data passes the noise filter (majority
decision by sampling the serial data input with the bus clock three times), and the passed data detects "L"
at the sampling point.
Figure 7-29 From ID Field Transmission to Data Field Transmission/Reception
From ID Field Transmission to Data Field Transmission
LIN bus
DATA Field transmission
ID Field transmission
DATA Field write
SSR:TDRE
Synch Field
From ID Field Transmission to Data Field Reception
LIN bus
DATA Field reception
ID Field transmission
DATA Field read
SSR:TDRE
Synch Field
SSR:RDRF
Notes
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Although the noise filter (where the serial data input is sampled three times with the bus clock and
decided by majority) is built in, design the board so that the noise should not pass this filter or
communicate so that noise passing may not become a problem (for instance, when the error occurs due to
adding the checksum of data at the end, send it again).
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If a falling edge of serial data is detected at the same time as the sampling point of the stop bit or before
one to two bus clocks during reception, the data may not be received with the edge disabled. It is
recommended to leave a space between frames if successive frames are to be output.
MB91520 Series
MN705-00010-1v0-E
1595