topic Re: CAN PE uses peripheral clock in S32K

CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 03:39:29 GMT

1. The CAN PE clock uses a peripheral clock of 60M, and CAN can communicate normally without frequency division

2. When using 12 division frequency and the clock size is 5M, communication cannot be normal.

3. Unable to run correctly when using CAN PE clock and peripheral clock 60M, propagation segment 5, synchronization segment 1 is 3, and synchronization segment 2 is 1

4. When using CAN PE clock and peripheral clock 60M, the transmission segment is 7, synchronization segment 1 is 4, and synchronization segment 2 is 1, it can operate correctly

What is the reason for this? I would like to know how to communicate normally with a 12 division frequency and a clock size of 5M

Re: CAN PE uses peripheral clock

Senlent — Wed, 21 Jun 2023 06:11:18 GMT

Hi@chai_997128

Can you tell me which device you are using? S32K1 or others?

Re: CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 06:16:04 GMT

s32kf146

Re: CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 06:22:54 GMT

Is it correct to use a peripheral clock for CAN PE clock to obtain a clock size of 5M.

Re: CAN PE uses peripheral clock

Senlent — Wed, 21 Jun 2023 06:31:44 GMT

Hi@chai_997128

I don't quiet understand, how you can set the PE clock to 5MHz? It's totally unreasonable.

Re: CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 06:35:32 GMT

Want to have an 80% sampling point, maintain 10 Tq, clock needs to reach 5M, right? Please point out any misunderstandings, thank you.

Re: CAN PE uses peripheral clock

Senlent — Wed, 21 Jun 2023 07:40:41 GMT

Hi@chai_997128

Can you provide your configuration ? or

Can you tell me which IDE and SDK you're using? and bitrate you need, whether CAN FD is enabled.

I can help you with some reasonable flexcan configurations.

Re: CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 07:55:36 GMT

I did not use the SDK configuration and posted it: the system clock is configured to 60M

CAN0->CTRL1 |=(CAN_CTRL1_CLKSRC (1)); Using the system clock

CAN0->CTRL1=0u

|CAN_ CTRL1_ PRESDIV (11)/* Sys clock 5M/(11+1)=5M*/

|CAN_ CTRL1_ PSEG2 (1)/* Configure for 500 KHz bit time*/

|CAN_ CTRL1_ PSEG1 (2)/* Time quanta freq=10 time quanta x 500 KHz bit time=5MHz*/

|CAN_ CTRL1_ PROPSEG (3)/* PRESDIV+1=Fclksrc/Ftq=5 MHz/5 MHz=1*/

|CAN_ CTRL1_ RJW (1)/* PRESDIV=0*/

|CAN_ CTRL1_ SMP (1)/* PSEG2=Phase_ Seg2-1=4-1=3*/

|CAN_ CTRL1_ BOFFMSK (1)/* PSEG1=PSEG2=3*/

|CAN_ CTRL1_ BOFFREC (1); /*PROPSEG=Prop_ Seg-1=7-1=6 */* RJW: since Phase_ Seg2>=4, RJW+1=4 so RJW=3 */

/*SMP=1: use 3 bits per CAN sample*/

/*CLKsrc=0 (unchanged): Fcanclk=Fosc=8 MHz*/

/*Busoff interrupt enable*/

/*Busoff auto recovery disabled*/

I want to obtain a configuration with a sampling point of 80%.

Re: CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 07:59:21 GMT

use CAN，not use CAN FD

Re: CAN PE uses peripheral clock

Senlent — Wed, 21 Jun 2023 09:17:23 GMT

Hi@chai_997128

I didn't find any problem with this configuration, if there is any problem please let me know, I will take some time to test this code

Re: CAN PE uses peripheral clock

chai_997128 — Wed, 21 Jun 2023 09:52:10 GMT

Under this configuration, CAN cannot operate normally，please help check.thanks！

Re: CAN PE uses peripheral clock

chai_997128 — Sun, 25 Jun 2023 01:21:37 GMT

hi @Senlent May I ask if there are any results?

Re: CAN PE uses peripheral clock

Senlent — Sun, 25 Jun 2023 03:23:45 GMT

Hi@chai_997128

as your configuration,500kbps,80%,PE clock is 60MHz,works fine on myside.

please check CTRL->CLKSRC is set to 1 or not

Re: CAN PE uses peripheral clock

chai_997128 — Sun, 25 Jun 2023 03:34:20 GMT

CTRL->CLKSRC is set to 1.

Are you using s32kF146?

Re: CAN PE uses peripheral clock

chai_997128 — Sun, 25 Jun 2023 03:43:55 GMT

hi @Senlent Can CAN communicate normally and is there a verification?

Re: CAN PE uses peripheral clock

Senlent — Sun, 25 Jun 2023 05:56:50 GMT

Hi@chai_997128

I‘m using S32K146EVB board,

and as I know, we don't have such part number

Re: CAN PE uses peripheral clock

chai_997128 — Mon, 26 Jun 2023 07:09:12 GMT

Hi @Senlent When debugging this configuration, CTRL ->CLKSRC cannot be set to 1, but it can be set during single step operation.What could be the reason for this?

Re: CAN PE uses peripheral clock

Senlent — Mon, 26 Jun 2023 07:17:22 GMT

Hi@chai_997128

Re: CAN PE uses peripheral clock

Senlent — Mon, 26 Jun 2023 07:42:13 GMT

Hi@chai_997128

from the code your provided, there is something wrong here.

Re: CAN PE uses peripheral clock

chai_997128 — Mon, 26 Jun 2023 07:51:04 GMT

Hi @Senlent This value cannot still be set to 1, which is a strange phenomenon. All other codes are annotated, only setting CAN_ CTRL1_ CLKSRC, unable to set, running this CAN in one step_ CTRL1. The CLKSRC value can be set.