TDA4VL-Q1: CAN sampling rate is low

wl.wang

Part Number: TDA4VL-Q1

Tool/software:

Hi expert，

My SDK version is pdk_j721s2_08_05_00_36，Now we introduce a new CAN transceiver in MCU1_0 and configure it as follows. We found that the data domain sampling rate is too low.

MCAL config：

REG_0C=0x801c97 （MCAN_DBTP)

REG_1C=0x3e007e1f (MCAN_NBTP)

Vector VH6501 test result:

The target sample point of Data phase is 75%，now 68.75 is low.

Could you please help analyze why the data domain sampling rate is low?

best regards！

wl.wang

27 days ago

0 Tarun Mukesh Puvvada 27 days ago

TI__Mastermind 49936 points

Hello,

This E2E could help you

PROCESSOR-SDK-J721S2: The problem of CAN sampling point deviation

Regards

Tarun Mukesh

0 wl.wang 27 days ago in reply to Tarun Mukesh Puvvada

Intellectual 392 points

Hi expert，

The E2E post above explained some rules for setting CAN standard bit time, but did not mention specific measures. Could you please check if the MCAL configuration attached to my first post is reasonable?

best regards

wl.wang

0 Tarun Mukesh Puvvada 27 days ago in reply to wl.wang

TI__Mastermind 49936 points

Hello,

It is mentioned at last

I checked the CAN2.0 specification, there are some limitations here,

Length of Time Segments
• SYNC_SEG is 1 TIME QUANTUM long.
• PROP_SEG is programmable to be 1,2,...,8 TIME QUANTA long.
• PHASE_SEG1 is programmable to be 1,2,...,8 TIME QUANTA long.
• PHASE_SEG2 is the maximum of PHASE_SEG1 and the INFORMATION PROCESSING TIME
• The INFORMATION PROCESSING TIME is less than or equal to 2 TIME QUANTA long.
The total number of TIME QUANTA in a bit time has to be programmable at least from 8 to 25.

Your Values are deviating from this logic.

Regards

Tarun Mukesh

0 Yong Zhang 18 days ago in reply to Tarun Mukesh Puvvada

TI__Genius 17001 points

Dear Tarun.

customer fix them with choosing good parameters. close this ticket.

thanks a lot!

yong

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TDA4VL-Q1: CAN sampling rate is low