Datasheet

21.4.6. LIN commands
Clearing the LCMD[2] bit in LINCR register enables LIN commands.
As shown in Table 21-1, four functions controlled by the LCMD[1..0] bits of LINCR register are available
(see Figure 21-5).
21.4.6.1. Rx header / LIN abort function
This function (or state) is mainly the withdrawal mode of the controller.
When the controller has to execute a master task, this state is the start point before enabling a Tx Header
command.
When the controller has only to execute slave tasks, LIN header detection/acquisition is enabled as
background function. At the end of such an acquisition (Rx Header function), automatically the
appropriate flags are set, and in LIN 1.3, the LINDLR register is set with the uncoded length value.
This state is also the start point before enabling the Tx or the Rx Response command.
A running function (that is Tx Header, Tx or Rx Response) can be aborted by clearing LCMD[1..0] bits in
LINCR register. In this case, an abort flag - LABORT - in LINERR register will be set to inform the other
software tasks. No wait states are implemented, so, the abort command is taken into account
immediately.
Rx Header function is responsible for:
• The BREAK field detection
• The hardware re-synchronization analyzing the SYNCH field
• The reception of the PROTECTED IDENTIFIER field, the parity control and the update of the
LINDLR register in case of LIN 1.3
• The starting of the Frame_Time_Out
• The checking of the LIN communication integrity
21.4.6.2. Tx header function
In accordance with the LIN protocol, only the master task must enable this function. The header is sent in
the appropriate timed slots at the programmed baud rate (c.f. LINBRR & LINBTR registers).
The controller is responsible for:
• The transmission of the BREAK field - 13 dominant bits
• The transmission of the SYNCH field - character 0x55
• The transmission of the PROTECTED IDENTIFIER field. It is the full content of the LINIDR register
(automatic check bits included)
At the end of this transmission, the controller automatically returns to Rx Header / LIN Abort state (that is,
LCMD[1..0] = 00) after setting the appropriate flags. This function leaves the controller in the same setting
as after the Rx Header function. This means that, in LIN 1.3, the LINDLR register is set with the uncoded
length value at the end of the Tx Header function.
During this function, the controller is also responsible for:
• The starting of the Frame_Time_Out
• The checking of the LIN communication integrity
21.4.6.3. Rx & TX response functions
These functions are initiated by the slave task of a LIN node. They must be used after sending an header
(master task) or after receiving an header (considered as belonging to the slave task). When the TX
Response order is sent, the transmission begins. A Rx Response order can be sent up to the reception of
the last serial bit of the first byte (before the stop-bit).
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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