Atmel SAM9X25, Manual

Page: 835 / 1145

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11054A–ATARM–27-Jul-11
SAM9X25
835
11054A–ATARM–27-Jul-11
SAM9X25
The header is transmitted as soon as the identifier is written in the LIN Identifier register
(US_LINIR). At this moment the flag TXRDY falls.
The Break Field, the Synch Field and the Identifier Field are sent automatically one after the
other.
The Break Field consists of 13 dominant bits and 1 recessive bit, the Synch Field is the charac-
ter 0x55 and the Identifier corresponds to the character written in the LIN Identifier Register
(US_LINIR). The Identifier parity bits can be automatically computed and sent (see
Section
39.7.8.9 ).
The flag TXRDY rises when the identifier character is transferred into the Shift Register of the
transmitter.
As soon as the Synch Break Field is transmitted, the flag LINBK in the Channel Status register
(US_CSR) is set to 1. Likewise, as soon as the Identifier Field is sent, the flag LINID in the Chan-
nel Status register (US_CSR) is set to 1. These flags are reset by writing the bit RSTSTA to 1 in
the Control register (US_CR).
Figure 39-39. Header Transmission
TXD
Baud Rate
Clock
Start
Bit
Write
US_LINIR
1 0 1 0 1 0 1 0
TXRDY
Stop
Bit
Start
Bit
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7 Break Field
13 dominant bits (at 0)
Stop
Bit
Break
Delimiter
1 recessive bit
(at 1)
Synch Byte = 0x55
US_LINIR
ID
LINID
in US_CSR
LINBK
in US_CSR
Write RSTSTA=1
in US_CR