Datasheet

621
32117D–AVR-01/12
AT32UC3C
25.6.14 Bus Idle Time-out
If the LIN bus is inactive for a certain duration, the slave nodes shall automatically enter in sleep
mode. In the LIN 2.0 specification, this time-out is fixed at 4 seconds. In the LIN 1.3 specifica-
tion, it is fixed at 25000 Tbits.
In Slave Node configuration, the Receiver Time-out detects an idle condition on the RXD line.
When a time-out is detected, the bit TIMEOUT in the Channel Status Register (CSR) rises and
can generate an interrupt, thus indicating to the driver to go into sleep mode.
The time-out delay period (during which the receiver waits for a new character) is programmed
in the TO field of the Receiver Time-out Register (RTOR). If the TO field is programmed at 0, the
Receiver Time-out is disabled and no time-out is detected. The TIMEOUT bit in CSR remains at
0. Otherwise, the receiver loads a 17-bit counter with the value programmed in TO. This counter
is decremented at each bit period and reloaded each time a new character is received. If the
counter reaches 0, the TIMEOUT bit in the Status Register rises.
If STTTO is performed, the counter clock is stopped until a first character is received.
If RETTO is performed, the counter starts counting down immediately from the value TO.
Table 25-15. Receiver Time-out programming
LIN Specification Baud Rate Time-out period TO
2.0
1 000 bit/s
4s
4 000
2 400 bit/s 9 600
9 600 bit/s 38 400
19 200 bit/s 76 800
20 000 bit/s 80 000
1.3 - 25 000 Tbits 25 000