AWR1642: AWR1642, canfd can not running at 100kbps

Hi,

Please follow the the formula provided in the CANFD test application to set the required bit rate.

C:\ti\mmwave_sdk_03_05_00_04\packages\ti\drivers\canfd\test\xwr18xx\main.c

/* Configuring 1Mbps and 5Mbps as nominal and data bit-rate respectively
Prop seg: 8
Ph seg 1: 6
Ph Seg2 : 5
Sync jump: 1
BRP(Baud rate Prescaler): 2

Nominal Bit rate = (40)/(((8+6+5)+1)*BRP) = 1Mhz

Timing Params for Data Bit rate:
Prop seg: 2
Ph seg 1: 2
Ph Seg2 : 3
Sync jump: 1
BRP(Baud rate Prescaler): 1

Nominal Bit rate = (40)/(((2+2+3)+1)*BRP) = 5Mhz
*/

Hi  Jitendra Gupta,

As shown in the screenshot, I configured it according to this equation, when nomBrp=8, baud rate = (40)/(((8+6+5)+1)*8) = 0.25, 250kbps. So when nomBrp=20, the baud rate should be = (40)/((((8+6+5)+1)*20) = 0.1, 100kbps. but CANFD doesn't work at 100kbps after I configure it this way. Did I get something wrong? 

Thanks!

Hi,

Is an error code returned by the driver? If so, could you share the error code?

Regards,

Aayush

Hi,

sorry for the delay.

I don't see any errors returned by the driver, it just doesn't work.

These are the configurations I use for 100kbps:

g_mcanBitTimingParams.nomBrp = 0x20U;

g_mcanBitTimingParams.nomPropSeg = 0x8U;
g_mcanBitTimingParams.nomPseg1 = 0x6U;
g_mcanBitTimingParams.nomPseg2 = 0x5U;
g_mcanBitTimingParams.nomSjw = 0x1U;

g_mcanBitTimingParams.dataBrp = 0x1U;
g_mcanBitTimingParams.dataPropSeg = 0x2U;
g_mcanBitTimingParams.dataPseg1 = 0x2U;
g_mcanBitTimingParams.dataPseg2 = 0x3U;
g_mcanBitTimingParams.dataSjw = 0x1U;

If I change the nomBrp from 20 to 8, CAN will work normally at 250kbps.

If I change the nomBrp from 20 to 16, CAN can not work at 125kbps.

Could you please give me a set of parameters to make can bus work at 100kbps or 125kbps?

Thanks a lot !

Hi,

I will bring this to Jitendra's attention. Please let him get back to you by tomorrow as he is on leave today.

Regards,

Aayush

Hi Aayush,

Is there any update form Jitendra?

Hi,

I have consulted with the team. Here is the response I received:

Could you try out Nominal Bit rate = (40M)/((((16+2+1)+1)*20)) = 100 kbps?

With your current configuration, the sampling point might be below 50%

Regards,

Aayush

Hi,

I tried this set of parameters, but it still not working at 100kbps.

Are there any other parameters I can try?

Thanks!

Hi,

Let me go back to the team with this and see if we can debug this further.

Regards,

Aayush

Hi Aayush Mahajan,

Is there any progress?

Thanks!

Hi,

We have not done further experimentation on this. I would recommend reading the TRM chapter on CANFD and experimenting with the values to get this working. I have spoken internally, and the team has indicated that CANFD should work with 100kbps, but some tuning would be required for the configuration.

Regards,

Aayush