topic CAN0 : RX packets errors in iMX6Q in i.MX Processors

CAN0 : RX packets errors in iMX6Q

NANDESHSG — Thu, 07 Oct 2021 16:04:38 GMT

Hi All.

I am working on iMX6Q Custom board and i am using the Yocto Project Linux kernel Version 4.9.168,

in our project we are using msp432e (MSP432E401Y Arm® Cortex®-M4F, windows Environment) and iMX6Q processor (Linux Environment), The controller and processor interface using the CAN communication and both set to 1Mbps baud rate with triple sampling on,

In Imx6Q side some CAN frame are missing. to find the missing frames one side i used the CAN sniper in between msp432 and iMX6Q to get the data before reaching to imx6q, the CAN sniper connected to the linux pc or busmaster pc tool and other side i get the data from imx6q on target board, then i compare the both the logs, in iMX6q side frames are missing please refer the below image.

and on target side if i execute the ifconfig command in RX Packet errors are more appeared.

Can any one help me to resolve this issue,

I tried to decrease the baud rate 500000 also not work, and increase the #define FLEXCAN_MB_SIZE 16 to 32 here also Fail in CAN communication.

Re: CAN0 : RX packets errors in iMX6Q

kef2 — Thu, 07 Oct 2021 19:52:20 GMT

It could be timing mismatch. Perhaps odd CAN module clock on either iMX or MSP432, something like 66.(6) MHz, which doesn't divide by CAN bit rate. You may check it with

ip -details link show can0

Re: CAN0 : RX packets errors in iMX6Q

NANDESHSG — Fri, 08 Oct 2021 06:00:31 GMT

Hi Kef2,

Thanks for your quick reply,

i executed the above command it gives the following result.

SGN

Re: CAN0 : RX packets errors in iMX6Q

kef2 — Fri, 08 Oct 2021 07:26:09 GMT

30.0 MHz is OK.

Then try checking timings using scope. Disconnect node from the bus, let it send something and observe minimum pulse width on CANH/CANL. It should precisely match expected bitrate, 1.0us for 1Mbps, 2.0us for 500kbps etc. Any visible timing mismatch confirms timing is bad. Repeat the same with you other node.

Edward

Re: CAN0 : RX packets errors in iMX6Q

igorpadykov — Fri, 08 Oct 2021 11:53:48 GMT

Hi Nandish

for that issue may be recommended to try nxp linux from source.codeaurora.org/external/imx/linux-imx repository (as linux kernel version 4.9.168 is not supported by nxp)

https://source.codeaurora.org/external/imx/linux-imx/tree/?h=imx_4.9.88_2.0.0_ga

use simple can tests:

https://source.codeaurora.org/external/imx/imx-test/tree/test/can/doc?h=imx_4.9.88_2.0.0_ga

Best regards
igor

Re: CAN0 : RX packets errors in iMX6Q

NANDESHSG — Mon, 15 Nov 2021 07:40:35 GMT

Hello All,

i am trying to change the timeout delay as 50 to 250,

#define FLEXCAN_TIMEOUT_US (50) and

/* 8 for RX fifo and 2 error handling */
#define FLEXCAN_NAPI_WEIGHT (8 + 2) as #define FLEXCAN_NAPI_WEIGHT ( 64 ) /* 64 MB's */
but when is increase the time out error occurred bit late. but issue is same, can any one help me to come out of this problem.

Best Regards

Nandish S.G