![](http://datasheet.mmic.net.cn/100000/IF180C52TXXX-20R_datasheet_3493957/IF180C52TXXX-20R_388.png)
388
32099I–01/2012
AT32UC3L016/32/64
19.6.8.2
Slave Node Configuration
In this mode, the Peripheral DMA Controller transfers only data. The user reads the Identifier
from LINIR, and selects LIN mode by writing to LINMR. When NACT=PUBLISH the data is in the
write buffer, while the read buffer contains the data when NACT=SUBSCRIBE.
IMPORTANT: if in slave mode, NACT is already configured correctly as PUBLISH, the LINMR
register must still be written with this value in order to set TXRDY, and to request the corre-
sponding Peripheral DMA Controller write transfer.
Figure 19-35. Slave Node with Peripheral DMA Controller
19.6.9
Wake-up Request
Any node in a sleeping LIN cluster may request a wake-up. By writing to the Wakeup Signal
Type bit (LINMR.WKUPTYP), the user can choose to send either a LIN 1.3 (WKUPTYP=1), or a
LIN 2.0 (WKUPTYP=0) compliant wakeup request. Writing a one to the Send LIN Wakeup Sig-
nal bit (CR.LINWKUP), transmits a wakeup, and when completed sets LINTC.
According to LIN 1.3, the wakeup request should be generated with the character 0x80 in order
to impose eight successive dominant bits.
According to LIN 2.0, the wakeup request is issued by forcing the bus into the dominant state for
250s to 5ms. Sending the character 0xF0 does this, regardless of baud rate.
Baud rate max = 20 kbit/s -> one bit period = 50s -> five bit periods = 250s
Baud rate min = 1 kbit/s -> one bit period = 1ms -> five bit periods = 5ms
19.6.10
Bus Idle Time-out
LIN bus inactivity should eventually cause slaves to time-out and enter sleep mode. LIN 1.3
specifies this to 25000 bit periods, whilst LIN 2.0 specifies 4seconds. For the time-out counter
|
DATA 0
DATA N
RXRDY
Peripheral
Bus
READ BUFFER
NACT = SUBSCRIBE
DATA 0
DATA N
TXRDY
Peripheral
bus
WRITE BUFFER
USART LIN
CONTROLLER
USART LIN
CONTROLLER
Peripheral DMA
Controller
Peripheral DMA
Controller
Table 19-9.
Receiver Time-out Values (RTOR.TO)
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 bit periods
25 000