TJA1145 can't be waked up or can't receive the frame on the bus

[water9301]

Hi Nxp supporting Team,

We have one wake up issue about TJA1145 that under some conditions, TJA1145 can’t be waked up.

Condition is:

-CAN bus is about to enter sleep mode

-transceiver receive error frames on the bus

-send wake up frame(NM frame with correct PN information) before ECU go to power off mode

During this can’t wake up phase, we read out the register value:

Tes: 0x20, means PNFDE=1

Our question is:

Will this error cause the can't wakeup issue ?

How to fix it?

Btw, we use vector solution for the software.

Look forward to you reply.

Thanks in advance.

Look forward to you reply.

Thanks in advance.

[water9301]

Hi Jozef,

We are using TJA1145TK/FD variant.

Unfortunately, we didn't have any scope with oscilloscope, because it's not so convinent to capture the scope from the vehicle from customer side.

But we have many internal variables, regarding the current tranceivers status.

[JozefKozon]

Dear Huisheng, 

please see below an answer from an application engineer. It seems, the TJA1145 is in standby mode.

DESCRIPTION

setting the PNFDE = 1 should wake the device automatically.

With the description below, I can’t match the complaint “no wake-up” with the shown data list: assuming “ModeControlRead = 04h” means that reading the Mode Control register returns 0x04 => the device is in Standby mode => not in Sleep mode => awake => no problem?

Can you clarify this with the customer ?

With Best Regards,

Jozef

[water9301]

Hello Jozef,

Thanks for the support.

Maybe i didn't say it clearly.

What i mean is our ECU didn't send out the CAN message when this issue happens. At that point, NM with correct PN information can be seen on the bus, but NM state in our code is sleep state, the NM user data varialle is 0. That seems CAN data didn't pass the transceiver. 

So what confused us is when the PNFDE bit = 1, Can ECU still receive the data on bus?

and in which condition ,will this bit be set to 1?

Thanks.

[JozefKozon]

Hello Huisheng, 

please see below an answer from an application engineer. 

DESCRIPTION

PNFDE=1  stops PN decoding until PN gets re-enabled. And for receiving data from the CAN bus, the device must be in Normal mode and the transceiver must be in CAN Active or CAN Listen-only mode.

Data sheet extract:

“If the counter overflows (counter > 31), a frame detect

error is captured (PNFDE = 1) and the device wakes up; the counter is reset to zero when

the bias is switched off and partial networking is re-enabled.”

With Best Regards,

Jozef

[water9301]

Hello Jozef,

Thanks for the great support. 

Now it's clear to us for this issue. 

It's because of some error frames on the bus that cause the PNFDE bit to be 1. And when the bit set to 1, our software didn't regard it as a valid wake up source, so CAN is still in sleep state and the transceiver is not in normal state.

[JozefKozon]

Dear Huisheng, 

please state the TJA1145 full part number. Which of these four are you using?

Please check the top marking of the chip for the part number.

Please share a scope of the wake-up frame from an oscilloscope. 

With Best Regards,

Jozef