Datasheet

515
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
Figure 31-48. Master Node Configuration, NACT=IGNORE
31.7.8.21 Slave Node Configuration
• 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 register, must be write with
NACT = PUBLISH even if this field is already correctly configured, in order to set the TXREADY flag and the corre-
sponding PDC 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