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

795

SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]

11063K–ATARM–05-Nov-13



Write TXEN and RXEN in US_CR to enable both the transmitter and the receiver.



Write USART_MODE in US_MR to select the LIN mode and the Slave Node configuration.



Write CD and FP in US_BRGR to configure the baud rate.



Wait until LINID in US_CSR rises



Check LINISFE and LINPE errors



Read IDCHR in US_RHR



Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM and DLC in US_LINMR to configure the frame transfer.

IMPORTANT: If the NACT configuration for this frame is PUBLISH, the US_LINMR must be written with NACT =
PUBLISH even if this field is already correctly configured, in order to set the TXREADY flag and the corresponding write
transfer request.

What comes next depends on the NACT configuration:



Case 1: NACT = PUBLISH, the LIN controller sends the response



Wait until TXRDY in US_CSR rises



Write TCHR in US_THR to send a byte



If all the data have not been written, redo the two previous steps



Wait until LINTC in US_CSR rises



Check the LIN errors



Case 2: NACT = SUBSCRIBE, the USART receives the response



Wait until RXRDY in US_CSR rises



Read RCHR in US_RHR



If all the data have not been read, redo the two previous steps 



Wait until LINTC in US_CSR rises



Check the LIN errors



Case 3: NACT = IGNORE, the USART is not concerned by the response



Wait until LINTC in US_CSR rises



Check the LIN errors

TXRDY

Write

US_LINIR

RXRDY

LINTC

Break

Synch

Protected

Identifier

Data 1

Data N

Checksum

Data N-1

Header

Inter-

frame

space

Response

space

Frame

Frame slot = TFrame_Maximum

Response

Data3

FSDIS=1

FSDIS=0