UJA1076 Wake-up Sequence (Signal)

[maximillion]

I am using UJA 1076 and I put it to sleep mode. So I need wake-up sequence remotely.

According to the application note attached below, how should the wake-up message be?

What should the message ID of the CAN message be?

Should the time between frames be 0.5 - 3 us?

Is the message to be sent [0x01,0x00.0x01,0x00] without message ID?

 

[JozefKozon]

Dear Ufuk,

the whole wake-up recessive-dominant-recessive-dominant sequence occurred on the CAN bus must be shorter, than the tto(wake) time. 

At the same time, the recessive and dominant times must be minimally twake(busrec)min and twake(busdom)min respectively. 

Its best if you take the tto(wake) minimum value, 400us and the twake(busrec)min and twake(busdom)min maximum values. For both 3us. Even in this case you have plenty of time to conduct the wake-up recessive-dominant-recessive-dominant sequence within the tto(wake)=400us. 4*3us=12us.

The times between the recessive and dominant pulses is not stated.

Wtih Best Regards,

Jozef

[maximillion]

Dear Jozef, 

Firstly, I need to use the bitrate to time segments feature in the flexcan module to adjust the times you specify, right? 

According to what you wrote, no message IDs can be used, right?

Also, SBC woke up with CAN messages I sent randomly yesterday. Shouldn't it just wake up with recessive dominant recessive dominant sequences? Is this issue normal? 

Thanks for answering.

[JozefKozon]

Dear Ufuk,

you can disable the Bus wake-up detection with setting the STBCC bit to 0. If the STBCC is set to one, the recessive-dominant-recessive-dominant sequence will wake up the UJA1076. Yes, no message ID is required. 

When the UJA1076 woke-up with a random CAN message, can you please check if the message didn't contain the recessive-dominant-recessive-dominant sequence?

For example:

Or any other timing, but the recessive-dominant-recessive-dominant sequence within the 400us.

With Best Regards,

Jozef

[maximillion]

Dear Jozef,

I checked the CAN message. I have tried to two can messages which contain wake-up sequence and without wake-up sequence but SBC always wake-up.
Also, I need remote wake-up mechanism so I must not disable wake-up remotely.

[JozefKozon]

Dear Ufuk,

please confirm, that you are using the newer UJA1076A. There is also an obsolete UJA1076. Please check the top marking.

Could you please connect the oscilloscope to the CAN bus, when you are sending the random message which wakes up the SBC? And please share the scope. I would like to to check if the message doesn't contain the BUS wake-up pattern.

With Best Regards,

Jozef

[maximillion]

Dear @JozefKozon,

Firstly, Sorry for getting back to your reply late.

I have UJA1076A High-speed CAN core system basis chip. I'm not sure the wake up message was sent correctly.

I attached screenshot please check it.

[JozefKozon]

Dear Ufuk,

thank you for the scope. However this doesn't seem to be taken from the CANH and CANL differential pair pins. Is the signal taken from TXDC or RXDC pin? Could you please connect two probes on the CANH and CANL pins while the UJA1076A is in Sleep mode and please share a scope of pattern, which unwantedly woken-up the SBC?

The wake-up pattern doesn't need to contain the CAN ID, DATA, nor CRC value. Any pattern on the CANH and CANL pins will wake-up the SBC as long as it fulfills the CAN wake-up timing diagram in the Figure 9. 

With Best Regards,

Jozef

[maximillion]

Dear Jozef,

Signal received from TXDC I will share pattern of wake up for CANH and CANL as soon as possible.
I am using S32K148evb to send wake-up pattern message. I am not sure how to send can wake-up message without message ID or DATA. According to your information should I send only 0x0A

[JozefKozon · Accepted solution]

Dear Ufuk,

I didn't mean to send a CAN wake-up message to the UJA1076A. You have more devices on the CAN bus at the same time. While the UJA1076A is in Sleep mode and you communicate with other devices on the CAN bus, the UJA1076A unwantedly wakes-up. Is that correct? To wake-up the UJA1076A (willingly or unwillingly) you don't need to send any request. Just the pattern in the Figure 9. must appear on the CANH and CANL pins. 

With Best Regards,

Jozef