STMicroelectronics SPC572L series Reference Manual page 1424

LINFlexD
Header timeout mechanism
•
Master mode: As the header is generated by the LINFlexD, there are only two cases:
–
–
Therefore there is no meaning of header timeout in master mode, so it is disabled
•
Slave mode
–
–
–
–
The reset value of HTO is 45 and this register can only be programmed in slave mode.
As response space is not included in the response, frame timeout is no longer needed
and is removed completely. Indeed, header timeout and response timeout cover all
cases.
The timeout counter can be used to detect other timeouts. In this case, the MODE bit
must be set and the output compare value can be updated in the LINTOCR register by
software.
Stuck at zero timeout error
If the dominant pulse lasts for a time of at least 100 bits, the SZF bit in LINESR is set. If
the same dominant pulse prolongs, the subsequent SZF setting will be 87 bit times
apart (instead of 100 bit times).
50.3.2.5.7 Noise
During reception each bit is sampled 16 times and the value of the bit is obtained by taking
the majority value of the 8
value different from the other two, this error is flagged.
When OSR = 8, majority of 4
noise. Noise checking is disabled for all OSR less than eight.
This error is flagged when there is noise detected in the start bit (see
Error Status Register
50.3.2.6 Identifier filtering
In LIN protocol the identifier of a message is not associated with the address of a node but is
related to the content of the message. A transmitter broadcasts its message to all the
receivers. Based on the header received, the receiver decides whether to receive or
transmit a response (depending on the identifier value). If the message does not target the
node, it should be discarded.
To fulfill this requirement, the LINFlexD provides configurable filters in order to eliminate
software intervention. This hardware filtering saves CPU resources that would otherwise be
required to perform filtering by software.
There are a maximum of 16 filters (depending on the generic no_of_filters) in the LINFlexD,
which can be programmed by the user only during Initialization mode. In order to activate a
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no error on the bus and timing is correct (nominal header length)
an error occurs on the bus and LINFlexD flags it in LINESR register (typically a bit
error)
header_nominal = 13 + 2 + 10 + 10 = 35 Tbit
header_max = 1.4 × Header_nominal = 49 Tbit
taking into account a possible 14% clock deviation, header_max seen by
LINFlexD is 49 × 1.14 = 56 Tbit.
If the counter starts after 11 Tbit, the HTO value is 56 – 11 = 45 Tbit
th th
, 9
th
, 5
(LINESR)).
DocID027809 Rev 4
th
, and 10 samples. If any one of these three samples has a
th th
, and 6 samples are taken into account to determine
RM0400
Section 50.4.2.4, LIN