Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet

790

SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]

11063K–ATARM–05-Nov-13

A protected identifier consists of two subfields; the identifier and the identifier parity. Bits 0 to 5 are assigned to the
identifier and bits 6 and 7 are assigned to the parity.

The USART interface can generate/check these parity bits, but this feature can also be disabled. The user can choose
between two modes by the PARDIS bit of the LIN Mode register (US_LINMR):



PARDIS = 0:



During header transmission, the parity bits are computed and sent with the 6 least significant bits of the 
IDCHR field of the LIN Identifier register (US_LINIR). The bits 6 and 7 of this register are discarded.



During header reception, the parity bits of the identifier are checked. If the parity bits are wrong, an Identifier 
Parity error occurs (see 

). Only the 6 least significant bits of the IDCHR field are updated 

with the received Identifier. The bits 6 and 7 are stuck to 0.



PARDIS = 1:



During header transmission, all the bits of the IDCHR field of the LIN Identifier register (US_LINIR) are sent 
on the bus. 



During header reception, all the bits of the IDCHR field are updated with the received Identifier.

In function of the identifier, the node is concerned, or not, by the LIN response. Consequently, after sending or receiving
the identifier, the USART must be configured. There are three possible configurations:



PUBLISH: the node sends the response.



SUBSCRIBE: the node receives the response.



IGNORE: the node is not concerned by the response, it does not send and does not receive the response.

This configuration is made by the field, Node Action (NACT), in the US_LINMR register (see 

Example: a LIN cluster that contains a Master and two Slaves:



Data transfer from the Master to the Slave 1 and to the Slave 2:

NACT(Master)=PUBLISH

NACT(Slave1)=SUBSCRIBE

NACT(Slave2)=SUBSCRIBE



Data transfer from the Master to the Slave 1 only:

NACT(Master)=PUBLISH

NACT(Slave1)=SUBSCRIBE

NACT(Slave2)=IGNORE



Data transfer from the Slave 1 to the Master:

NACT(Master)=SUBSCRIBE

NACT(Slave1)=PUBLISH

NACT(Slave2)=IGNORE



Data transfer from the Slave1 to the Slave2:

NACT(Master)=IGNORE

NACT(Slave1)=PUBLISH

NACT(Slave2)=SUBSCRIBE



Data transfer from the Slave2 to the Master and to the Slave1:

NACT(Master)=SUBSCRIBE

NACT(Slave1)=SUBSCRIBE

NACT(Slave2)=PUBLISH