Does TJA1145 support wakeup by CANFD message?

[AmosChen]

Does TJA1145 support wakeup by CANFD message? Which specific type should I choose？ Thanks！

[bcmtoyota]

Hello Tomas,

We have a related question.

Background: TJA1145ATK/FD is used. CFDC bit is set to 1. Intention to ignore CANFD message and wakeup on NM frame (CAN message) with specific range of CAN message IDs and data bytes (ID Mask and Data mask registers) are configured.

Normal functionality is fine. It wakes up on CAN message IDs with atleast one PN bit set in data bytes.

Scenario1: Lets say the DUT (Device under test) goes to sleep state with above configuration. And the other node (in bench setup it can be a CANalyzer or Canoe; in vehicle setup it can be another peer node / Partial network requester node) transmits any CAN / CANFD message other than the configured range for NM messages OR valid NM message ID but without the valid PN bits set configured for DUT. In this case, DUT does not wakeup and this is expected behavior. But the transmitting node reports ACK error (as the DUT is in sleep state and does not ACK). The transmitting node tries to resend only that message. So it does not get a chance to send any other message and reaches "Error passive" state when TX error count > 127. DUT does not wakeup as long as it does not receive valid NM message with valid PN bits. So this results in a deadlock. How can this deadlock be avoided?

Scenario2: In Bench setup CANalyzer or Canoe gives a option of "Self-ACK". With this option Canoe simulates self ACK and does not need a receiving node to ACK. With this configuration above dead lock is not observed. (this is only temporary option as in Vehicle there should be a real node to ACK). But with this option observe that DUT does not wakeup on "single" valid NM message with valid PN bits. It needs more than 1 NM messages at ~100ms to wakeup. If the 2nd message comes slower (Ex: after 1sec) then also TJA1145 does not wakeup. Is there any explanation for this? 

Thanks,

Manjunath BC

[TomasVaverka · Accepted solution]

Hello Chen,

If you use the TJA1145A (/FD is excluded), CFDC bit is not available and CAN FD data is detected as error, then error counter incremented.
If error counter overflow happens (>31), TJA1145A is forced to wake up (with error status PNFDE=1 indicate).

This cannot fulfill requirement for CAN FD passive, so TJA1145A/FD is prepared for CAN FD passive use case.
TJA1145A/FD offers CFDC bit and error counter decrement when CAN FD data was detected if CFDC=1 was selected.
Then, wake up never happens (even if ID was valid) when CAN input signal includes CAN FD data field.
This is preferred behavior for CAN FD passive requirement.

For more details, please refer to the attached AH1203 and AH1309.

Best regards,

Tomas