LPC5536 CAN ID Filter

[alvarolopes]

Hi,

I am creating a project with LP5536 that I need to use 6 ID Filters, but I am facing some problems. I started using SDK example that have only ID Filter. When I tried to use 6 ID Filters the code generated an error during the CAN initialization:

"MCAN Message RAM configuration failed, please check parameters!"

Follow my code and definitions:

#define TX_BUFFER_OFS 0x20U

#define MSG_RAM_SIZE (TX_BUFFER_OFS + 8 + CAN_DATASIZE)

#define CAN_DATASIZE (64U)

mcan_config_t mcanConfig;

mcan_memory_config_t memoryConfig = {0};

mcan_frame_filter_config_t rxFilter = {0};

mcan_std_filter_element_config_t stdFilter = {0};

mcan_rx_fifo_config_t rxFifo0 = {0};

mcan_tx_buffer_config_t txBuffer = {0};

CLOCK_SetClkDiv(kCLOCK_DivCanClk, 5U, true);

CLOCK_AttachClk(kMCAN_DIV_to_MCAN);

MCAN_GetDefaultConfig(&mcanConfig);

mcan_timing_config_t timing_config;

memset(&timing_config, 0, sizeof(timing_config));

if (MCAN_CalculateImprovedTimingValues(mcanConfig.baudRateA, MCAN_CLK_FREQ, &timing_config))

{

/* Update the improved timing configuration*/

memcpy(&(mcanConfig.timingConfig), &timing_config, sizeof(mcan_timing_config_t));

}

else

{

PRINTF("No found Improved Timing Configuration. use default configuration\r\n\r\n");

}

mcanConfig.baudRateA = CAN1_SPEED_100kBit;

MCAN_Init(EXAMPLE_MCAN, &mcanConfig, MCAN_CLK_FREQ);

memoryConfig.baseAddr = (uint32_t)msgRam;

/* STD filter config. */

rxFilter.address = STD_FILTER_OFS;

rxFilter.idFormat = kMCAN_FrameIDStandard;

rxFilter.listSize = 6U;

rxFilter.nmFrame = kMCAN_reject0;

rxFilter.remFrame = kMCAN_rejectFrame;

memoryConfig.stdFilterCfg = &rxFilter;

/* RX fifo0 config. */

rxFifo0.address = RX_FIFO0_OFS;

rxFifo0.elementSize = 1U;

rxFifo0.watermark = 0;

rxFifo0.opmode = kMCAN_FifoBlocking;

//rxFifo0.datafieldSize = kMCAN_8ByteDatafield;

rxFifo0.datafieldSize = kMCAN_64ByteDatafield;

memoryConfig.rxFifo0Cfg = &rxFifo0;

/* TX buffer config. */

txBuffer.address = TX_BUFFER_OFS;

txBuffer.dedicatedSize = 1U;

txBuffer.fqSize = 0;

txBuffer.datafieldSize = kMCAN_8ByteDatafield;

memoryConfig.txBufferCfg = &txBuffer;

/* Set Message RAM config and clear memory to avoid BEU/BEC error. */

memset((void *)msgRam, 0, MSG_RAM_SIZE * sizeof(uint8_t));

if (kStatus_Success != MCAN_SetMessageRamConfig(EXAMPLE_MCAN, &memoryConfig))

{

PRINTF("MCAN Message RAM configuration failed, please check parameters!\r\n");

return -1;

}

 If anyone has a tip to help me, I would appreciate.

Regards!

[carlos_o]

Hi @alvarolopes 

Thanks for your post

Could you please share which version of MCUXpresso and the SDK are you using?

You mentioned that the issue happens at the can initialization, but error log you share is from "

if (kStatus_Success != MCAN_SetMessageRamConfig(EXAMPLE_MCAN, &memoryConfig))

{

PRINTF("MCAN Message RAM configuration failed, please check parameters!\r\n");

return -1;

}

"

Please debug the MCAN_SetMessageRamConfig function and share where the code is going to kStatus_Fail

[alvarolopes]

MCUXpresso version:

MCUXpresso IDE v25.6

The problem happens when I use more than 4 ID filters (rxFilter.listSize).

Follow my entire code:

mcan_config_t mcanConfig;

    mcan_memory_config_t memoryConfig          = {0};

    mcan_frame_filter_config_t rxFilter        = {0};

    mcan_std_filter_element_config_t stdFilter = {0};

    mcan_rx_fifo_config_t rxFifo0    = {0};

    mcan_tx_buffer_config_t txBuffer = {0};

    /* Initialize board hardware. */

    //BOARD_InitHardware();

    //Set MCAN clock 100Mhz/5=20MHz.

    CLOCK_SetClkDiv(kCLOCK_DivCanClk, 5U, true);

    CLOCK_AttachClk(kMCAN_DIV_to_MCAN);

    PRINTF("\r\n==MCAN loopback functional example -- Start.==\r\n\r\n");

    /* Get MCAN module default Configuration. */

    /*

     * mcanConfig.baudRate               = 500000U;

     * mcanConfig.baudRateFD             = 2000000U;

     * mcanConfig.enableCanfdNormal      = false;

     * mcanConfig.enableCanfdSwitch      = false;

     * mcanConfig.enableLoopBackInt      = false;

     * mcanConfig.enableLoopBackExt      = false;

     * mcanConfig.enableBusMon           = false;

     */

    MCAN_GetDefaultConfig(&mcanConfig);

    /* Enable external loop back mode.

     * Current node treats its own transmitted messages as received messages,

     * Other node can receive Current node transmitted messages,

     * Other node can't transmit messages or ACK signal to Current node.

     */

    //mcanConfig.enableLoopBackExt = true;

    mcan_timing_config_t timing_config;

    memset(&timing_config, 0, sizeof(timing_config));

    if (MCAN_CalculateImprovedTimingValues(mcanConfig.baudRateA, MCAN_CLK_FREQ, &timing_config))

    {

        /* Update the improved timing configuration*/

        memcpy(&(mcanConfig.timingConfig), &timing_config, sizeof(mcan_timing_config_t));

    }

    else

    {

        PRINTF("No found Improved Timing Configuration. use default configuration\r\n\r\n");

    }

mcanConfig.baudRateA = CAN1_SPEED_100kBit;

    MCAN_Init(EXAMPLE_MCAN, &mcanConfig, MCAN_CLK_FREQ);

    memoryConfig.baseAddr = (uint32_t)msgRam;

    /* STD filter config. */

    rxFilter.address          = STD_FILTER_OFS;

    rxFilter.idFormat         = kMCAN_FrameIDStandard;

    rxFilter.listSize         = 6U;

    rxFilter.nmFrame          = kMCAN_reject0;

    rxFilter.remFrame         = kMCAN_rejectFrame;

    memoryConfig.stdFilterCfg = &rxFilter;

    /* RX fifo0 config. */

    rxFifo0.address       = RX_FIFO0_OFS;

    rxFifo0.elementSize   = 1U;

    rxFifo0.watermark     = 0;

    rxFifo0.opmode        = kMCAN_FifoBlocking;

    rxFifo0.datafieldSize = kMCAN_8ByteDatafield;

    memoryConfig.rxFifo0Cfg = &rxFifo0;

    /* TX buffer config. */

    txBuffer.address       = TX_BUFFER_OFS;

    txBuffer.dedicatedSize = 1U;

    txBuffer.fqSize        = 0;

    txBuffer.datafieldSize = kMCAN_8ByteDatafield;

    memoryConfig.txBufferCfg = &txBuffer;

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Follow is when the error occurs

    /* Set Message RAM config and clear memory to avoid BEU/BEC error. */

    memset((void *)msgRam, 0, MSG_RAM_SIZE * sizeof(uint8_t));

    if (kStatus_Success != MCAN_SetMessageRamConfig(EXAMPLE_MCAN, &memoryConfig))

    {

        PRINTF("MCAN Message RAM configuration failed, please check parameters!\r\n");

        return -1;

    }

If you put     "rxFilter.listSize > 4" , the message "MCAN Message RAM configuration failed, please check parameters!" will be displayed.

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And follow my filters:

stdFilter.sfec = kMCAN_storeinFifo0;

//Classic filter mode, only filter matching ID.

stdFilter.sft   = kMCAN_classic;

stdFilter.sfid1 = 0x4B0U;

stdFilter.sfid2 = 0x7FFU;

MCAN_SetSTDFilterElement(EXAMPLE_MCAN, &rxFilter, &stdFilter, 0);

stdFilter.sfec = kMCAN_storeinFifo0;

//Classic filter mode, only filter matching ID.

stdFilter.sft   = kMCAN_classic;

stdFilter.sfid1 = 0x600U;

stdFilter.sfid2 = 0x7FFU;

MCAN_SetSTDFilterElement(EXAMPLE_MCAN, &rxFilter, &stdFilter, 1);

stdFilter.sfec = kMCAN_storeinFifo0;

//Classic filter mode, only filter matching ID.

stdFilter.sft   = kMCAN_classic;

stdFilter.sfid1 = 0x1a1U;

stdFilter.sfid2 = 0x7FFU;

MCAN_SetSTDFilterElement(EXAMPLE_MCAN, &rxFilter, &stdFilter, 2);

stdFilter.sfec = kMCAN_storeinFifo0;

//Classic filter mode, only filter matching ID.

stdFilter.sft   = kMCAN_classic;

stdFilter.sfid1 = 0x2a2U;

stdFilter.sfid2 = 0x7FFU;

MCAN_SetSTDFilterElement(EXAMPLE_MCAN, &rxFilter, &stdFilter, 3);

stdFilter.sfec = kMCAN_storeinFifo0;

//Classic filter mode, only filter matching ID.

stdFilter.sft   = kMCAN_classic;

stdFilter.sfid1 = 0x421U;

stdFilter.sfid2 = 0x7FFU;

MCAN_SetSTDFilterElement(EXAMPLE_MCAN, &rxFilter, &stdFilter, 4);

stdFilter.sfec = kMCAN_storeinFifo0;

//Classic filter mode, only filter matching ID.

stdFilter.sft   = kMCAN_classic;

stdFilter.sfid1 = 0x100U;

stdFilter.sfid2 = 0x7FFU;

MCAN_SetSTDFilterElement(EXAMPLE_MCAN, &rxFilter, &stdFilter, 5);

    /* Enable RX fifo0 new message interrupt using interrupt line 0. */

    MCAN_EnableInterrupts(EXAMPLE_MCAN, 0, CAN_IE_RF0NE_MASK);

    EnableIRQ(CAN0_IRQ0_IRQn);

Regards,

Alvaro

[carlos_o]

Hi @alvarolopes 

The MCAN_SetMessageRamConfig function fail due to wrong address parameter, this is related to memoryConfig configuration. 

Please make sure msgRam has 4k alignment.

Also share the value of MSG_RAM_SIZE 

[alvarolopes]

#define MSG_RAM_BASE 0x04000000U

#define TX_BUFFER_OFS 0x20U

#define CAN_DATASIZE (64U)

#define MSG_RAM_SIZE (TX_BUFFER_OFS + 8 + CAN_DATASIZE)

How can I know if my RAM has 4k alignment?

Regards,

Alvaro

[carlos_o]

Hi @alvarolopes 

Apologies the late reply

I do some test at my end and I've found the following:

To have more than 4 filters you need to modify the rxFifo0.address value to be at least 4 * rxFilter.listsize so you need rxFifo0.address be equal to 0x18 at minimum to support 6 filters. 

Regarding the alignment question to ensure the start of msg_ram to be align you only need to ensure that the value of MSG_RAM_BASE is divisible per 0x1000, the value you assign is aligned. 

Let me know if this information solves the issue. 

[alvarolopes]

Hello my friend. Excuse me for delay.

Good news. It works, but I needed to change the register txBuffer.address to

0x28.

The final configuration was:

RX_FIFO0_OFS = 0x18

rxFifo0.address = RX_FIFO0_OFS;

TX_BUFFER_OFS = 0x28

txBuffer.address = TX_BUFFER_OFS;

Regards,

Alvaro

[carlos_o]

Hi @alvarolopes 

Great to hear that!

Thanks for letting me know and share the configurations that works for you.