OPTIREG™ SBC TLE9274QXV33
High-speed CAN transceiver
8.2.3
CAN Receive-Only mode
In CAN Receive-Only mode (RX only), the driver stage is disabled but reception is still operational. This mode
is accessible by an SPI command in SBC Normal mode and in SBC Stop mode.
Note: The transceiver is still working properly in Receive-Only mode even if VCAN is not available because of an
independent receiver supply.
8.2.4
CAN Wake-capable mode (wake-up pattern)
This mode can be used in SBC Stop, Sleep, Restart and Normal mode by programming via SPI and it is used to
monitor bus activities. It is automatically accessed in SBC Fail-Safe mode. A wake-up pattern on the bus
results in a change of behavior of the SBC, as described in Table 12. As a signal to the microcontroller, the
RXDCAN pin is set to low and will stay low until the CAN transceiver changes to a different mode. After a wake-
up pattern event, the transceiver can be switched to CAN Normal mode via SPI for bus communication.
As shown in Figure 21, a wake-up pattern is signaled on the bus by two consecutive dominant bus levels for
at least tWake1 (filter time t > tWake1) and less than tWake2, each separated by a recessive bus level greater than
tWake1 and shorter than tWake2.
Entering CAN wake
capable
Bus recessive > tWAKE1
Bus dominant > tWAKE1
Ini
Bias off
Wait
Bias off
tWAKE2 expired
1
Bias off
Bus recessive > tWAKE1
t
WAKE2 expired
2
Bias off
Bus dominant > tWAKE1
Entering CAN Normal
or CAN Recive Only
3
Bias on
Figure 21 CAN wake-up pattern detection (WUP) according to the definition in ISO 11898-5
Rearming the transceiver for wake capability
After a BUS wake-up pattern event, the transceiver is woken. However, the CAN transceiver mode bits will still
show wake capable (=‘01’) so the RXDCAN signal will be pulled LOW. There are two possibilities for enabling
the CAN transceiver’s wake capable mode again after a wake-up event:
Datasheet
50
Rev.2.0
2022-05-06
INFINEON [ Infineon ]
