How to config Freemaster over CAN bus?

[Jimny]

Hello,

I want to use freemaster to communicate with the mcu over CAN bus.

I have googled the tutorial but found nothing. Is there any demo which can explain the basic how-to? I want to know how to add the related code to my project in S32DS. I am using S32K144-EVB.

[iulian_stan]

Hi @Jimny,

Could you please provide some additional details about your case:

• Are you trying to add FreeMASTER Driver to you project and configure it for CAN communication or the Driver is already enabled and you have issues configuring it ?
• What versions of S32DS IDE and S32K1xx SDK are you using ?

In the meantime you can check this post - it's a bit outdated, but can give a base understanding of FreeMASTER Driver. I will provide updated instructions to match the tools you are working with.

Kind regards,
Iulian

[Jimny]

Hello, iulianstan

Thank you for your reply.

The driver is already enabled and I have issues configuring it.

I use S32DS for ARM 2.2 and S32K144_SDK 3.0.0.

Let me describe the issue in detail.

I have created a new project and configure the can_pal.

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I have changed the configuration in freemaster_cfg.h to use the can bus.

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In the main function, I initialized the clock and can peripherals. And the FMSTR_Init(), FMSTR_Poll() functions were also added.

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Then I compiled the program and flashed it.

A freemaster project has been created to test the demo. I choose to connect the board over can bus.

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Then I clicked the Plug-in Configuration.

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I use GY8507 interface card from GLINKER. It seems the driver is ok. When I clicked the Test Connection, an error occured.

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I think I should have missed  some configuration in the code. Please see the project in the attachment.

By the way, I have tested the model in the MBDT named "CAN_With_FreeMASTER_over_CAN", it works.

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[iulian_stan · Accepted solution]

Hi @Jimny,

There are 2 things that need minor adjustments, one is in your code and another one related to the SDK:

• In your code: you are using Short Interrupt Mode (#define FMSTR_SHORT_INTR 1) but you miss the piece that attaches FreeMASTER handler to CAN communication interrupt
  

  #if FMSTR_SHORT_INTR || FMSTR_LONG_INTR
      INT_SYS_InstallHandler(CAN0_ORed_0_15_MB_IRQn, FMSTR_Isr, NULL);
      INT_SYS_EnableIRQ(CAN0_ORed_0_15_MB_IRQn);
  #endif​

   If you don't want to use interrupts, you can switch to polling mode:
  

  #define FMSTR_LONG_INTR        0    /* Complete message processing in interrupt */
  #define FMSTR_SHORT_INTR       0    /* SCI FIFO-queuing done in interrupt */
  #define FMSTR_POLL_DRIVEN      1    /* No interrupt needed, polling only */​

• The SDK: this reply explains the change. TLDR add this snippet after CAN initialization: 
  

  /* Enter Freeze mode */
  CAN0->MCR |= (CAN_MCR_FRZ_MASK | CAN_MCR_HALT_MASK);
  CAN0->MCR &= ~CAN_MCR_MDIS_MASK;
  while((CAN0->MCR & CAN_MCR_FRZACK_MASK ) == 0){}
  /* Disable abort mechanism  MCR[AEN] = 0 */
  CAN0->MCR &= ~CAN_MCR_AEN_MASK;
  /* Enable the FlexCAN module */
  CAN0->MCR &= ~(CAN_MCR_FRZ_MASK | CAN_MCR_HALT_MASK);​

I also attached my main.c that should work in both modes. Let me know if it helps fixing your issue.

Regards,
Iulian

[Jimny]

Hi, @iulian_stan 

Your solution works! Thank you very much.