TLE8263-2E Datasheet, PDF (33/94 Pages) Infineon Technologies AG – Universal System Basis Chip

TLE8263-2E
Confidential
High Speed CAN Transceiver
8.4
Failure Detection
All failures are reported in the SPI diagnostic encoder, the TxD time-out is reported as TxD shorted to GND. In
case of local failure and Bus Dominat Clamped failure, the transceiver is automatically switched to the CAN
Receive only Mode.
8.4.1 TxD Time-out Feature
If the TxD signal is dominant for a time t > t_TxD, the TxD time-out function deactivates the transmission of the signal
at the bus. This is implemented to prevent the bus from being blocked permanently due to an error. The
transmission is released after switching the CAN to Active Mode via SPI. Refer to Figure 12.
TxDCAN
VC C1µC
TxD Time -out
Interrupt
SPI setting : CAN
Normal Mode
GND
t
V_diff
tTxD_TO
Figure 12 TxD Time-out diagram
t
Txd timeout .vsd
8.4.2 Bus Dominant Clamping
If the HS CAN bus signal in dominant for a time t > t_{BUS_TO}, a bus dominant clamping is detected. The CAN
transceiver is switched to Receive Only Mode. The failure is signaled via SPI. If the bits are not masked the INT
pin is set to low. For operation the transceiver needs to be switched back to Normal Mode via SPI.
8.4.3 TxD to RxD Short Circuit Feature
Similar to the TxD time-out, a TxD to RxD short circuit would also block the bus communication. To avoid this, the
CAN transceiver provides TxD to RxD short circuit detection. In this case, it is recommended to switch OFF the
SBC HS CAN supply (e.g. V_cc2) via SPI command to prevent disturbances on the CAN bus. This failure is reported
into the diagnostic frame of the SPI. The INT pin is set LOW if not disabled via SPI. The transmitter is automatically
inhibited and goes back to normal operation after a SPI command.
8.4.4 Overtemperature
The driver stages are protected against overtemperature. Exceeding the shutdown temperature results in
deactivation of the CAN transceiver. The CAN transceiver is activated gain after cooling down, the device stays in
CAN Active Mode. To avoid a bit failure after cooling down, the signals can be transmitted again only after a
dominant to recessive edge at TxD.
Figure 13 shows how the transmission stage is deactivated and activated again. First, an overtemperature
condition causes the CAN transceiver to be deactivated. After the overtemperature condition is no longer present,
the transmission is released automatically after the TxD bus signal has changed to recessive level.
Data Sheet
33
Rev. 1.0, 2009-03-31