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TCAN4550: TCAN4550 Problem

Part Number: TCAN4550


Hi team,

After configuring TCAN4550,the output waveform is as follow:

The question is why has that happened. Do you have any suggestion? The code is as follows:

/*********************************************
* Everything at this point is for TCAN4550 *
*********************************************/
Init_CAN(); // Run the main MCAN configuration sequence. The bulk of the configuration is in this!

/* Define the CAN message we want to send*/
TCAN4x5x_MCAN_TX_Header header = {0}; // Remember to initialize to 0, or you'll get random garbage!
uint8_t data[8] = {0xff, 0xff, 0xff, 0xff,0xff,0xff,0x55,0x55}; // Define the data payload
header.DLC = MCAN_DLC_8B; // Set the DLC to be equal to or less than the data payload (it is ok to pass a 64 byte data array into the WriteTXFIFO function if your DLC is 8 bytes, only the first 8 bytes will be read)
header.ID = 0x05f; // Set the ID
header.FDF = 0; // CAN FD frame enabled 1
header.BRS = 0; // Bit rate switch enabled
header.EFC = 0;
header.MM = 0;
header.RTR = 0;
header.XTD = 0; // We are not using an extended ID in this example
header.ESI = 0; // Error state indicator


TCAN4x5x_MCAN_WriteTXBuffer(0, &header, data); // This function actually writes the header and data payload to the TCAN's MRAM in the specified TX queue number. It returns the bit necessary to write to TXBAR,
// but does not necessarily require you to use it. In this example, we won't, so that we can send the data queued up at a later point.

TCAN4x5x_MCAN_TransmitBufferContents(0); // Request that TX Buffer 0 be transmitted

配置如下:

void
Init_CAN(void)
{
uint32_t a;
TCAN4x5x_Device_ClearSPIERR(); // Clear any SPI ERR flags that might be set as a result of our pin mux changing during MCU startup
a=AHB_READ_32(REG_SPI_DEVICE_ID0);
a=AHB_READ_32(REG_SPI_DEVICE_ID1);
/* Step one attempt to clear all interrupts */
TCAN4x5x_Device_Interrupt_Enable dev_ie = {0}; // Initialize to 0 to all bits are set to 0.
TCAN4x5x_Device_ConfigureInterruptEnable(&dev_ie); // Disable all non-MCAN related interrupts for simplicity

TCAN4x5x_Device_Interrupts dev_ir = {0}; // Setup a new MCAN IR object for easy interrupt checking
TCAN4x5x_Device_ReadInterrupts(&dev_ir); // Request that the struct be updated with current DEVICE (not MCAN) interrupt values

if (dev_ir.PWRON) // If the Power On interrupt flag is set
TCAN4x5x_Device_ClearInterrupts(&dev_ir); // Clear it because if it's not cleared within ~4 minutes, it goes to sleep

/* Configure the CAN bus speeds */
TCAN4x5x_MCAN_Nominal_Timing_Simple TCANNomTiming = {0}; // 500k arbitration with a 40 MHz crystal ((40E6 / 2) / (32 + 8) = 500E3)
TCANNomTiming.NominalBitRatePrescaler = 2;
TCANNomTiming.NominalTqBeforeSamplePoint = 32;
TCANNomTiming.NominalTqAfterSamplePoint = 8;

TCAN4x5x_MCAN_Data_Timing_Simple TCANDataTiming = {0}; // 2 Mbps CAN FD with a 40 MHz crystal (40E6 / (15 + 5) = 2E6)
TCANDataTiming.DataBitRatePrescaler = 1;
TCANDataTiming.DataTqBeforeSamplePoint = 15;
TCANDataTiming.DataTqAfterSamplePoint = 5;

/* Configure the MCAN core settings */
TCAN4x5x_MCAN_CCCR_Config cccrConfig = {0}; // Remember to initialize to 0, or you'll get random garbage!
cccrConfig.FDOE = 0; // CAN FD mode enable
cccrConfig.BRSE = 0; // CAN FD Bit rate switch enable

/* Configure the default CAN packet filtering settings */
TCAN4x5x_MCAN_Global_Filter_Configuration gfc = {0};
gfc.RRFE = 1; // Reject remote frames (TCAN4x5x doesn't support this)
gfc.RRFS = 1; // Reject remote frames (TCAN4x5x doesn't support this)
gfc.ANFE = TCAN4x5x_GFC_ACCEPT_INTO_RXFIFO0; // Default behavior if incoming message doesn't match a filter is to accept into RXFIO0 for extended ID messages (29 bit IDs)
gfc.ANFS = TCAN4x5x_GFC_ACCEPT_INTO_RXFIFO0; // Default behavior if incoming message doesn't match a filter is to accept into RXFIO0 for standard ID messages (11 bit IDs)

/* ************************************************************************
* In the next configuration block, we will set the MCAN core up to have:
* - 1 SID filter element
* - 1 XID Filter element
* - 5 RX FIFO 0 elements
* - RX FIFO 0 supports data payloads up to 64 bytes
* - RX FIFO 1 and RX Buffer will not have any elements, but we still set their data payload sizes, even though it's not required
* - No TX Event FIFOs
* - 2 Transmit buffers supporting up to 64 bytes of data payload
*/
TCAN4x5x_MRAM_Config MRAMConfiguration = {0};
MRAMConfiguration.SIDNumElements = 1; // Standard ID number of elements, you MUST have a filter written to MRAM for each element defined
MRAMConfiguration.XIDNumElements = 1; // Extended ID number of elements, you MUST have a filter written to MRAM for each element defined
MRAMConfiguration.Rx0NumElements = 5; // RX0 Number of elements
MRAMConfiguration.Rx0ElementSize = MRAM_64_Byte_Data; // RX0 data payload size
MRAMConfiguration.Rx1NumElements = 0; // RX1 number of elements
MRAMConfiguration.Rx1ElementSize = MRAM_64_Byte_Data; // RX1 data payload size
MRAMConfiguration.RxBufNumElements = 0; // RX buffer number of elements
MRAMConfiguration.RxBufElementSize = MRAM_64_Byte_Data; // RX buffer data payload size
MRAMConfiguration.TxEventFIFONumElements = 0; // TX Event FIFO number of elements
MRAMConfiguration.TxBufferNumElements = 2; // TX buffer number of elements 2
MRAMConfiguration.TxBufferElementSize = MRAM_64_Byte_Data; // TX buffer data payload size


/* Configure the MCAN core with the settings above, the changes in this block are write protected registers, *
* so it makes the most sense to do them all at once, so we only unlock and lock once */

TCAN4x5x_MCAN_EnableProtectedRegisters(); // Start by making protected registers accessible
TCAN4x5x_MCAN_ConfigureCCCRRegister(&cccrConfig); // Enable FD mode and Bit rate switching
TCAN4x5x_MCAN_ConfigureGlobalFilter(&gfc); // Configure the global filter configuration (Default CAN message behavior)
TCAN4x5x_MCAN_ConfigureNominalTiming_Simple(&TCANNomTiming);// Setup nominal/arbitration bit timing
TCAN4x5x_MCAN_ConfigureDataTiming_Simple(&TCANDataTiming); // Setup CAN FD timing
TCAN4x5x_MRAM_Clear(); // Clear all of MRAM (Writes 0's to all of it)
TCAN4x5x_MRAM_Configure(&MRAMConfiguration); // Set up the applicable registers related to MRAM configuration
TCAN4x5x_MCAN_DisableProtectedRegisters(); // Disable protected write and take device out of INIT mode


/* Set the interrupts we want to enable for MCAN */
TCAN4x5x_MCAN_Interrupt_Enable mcan_ie = {0}; // Remember to initialize to 0, or you'll get random garbage!
mcan_ie.RF0NE = 1; // RX FIFO 0 new message interrupt enable

TCAN4x5x_MCAN_ConfigureInterruptEnable(&mcan_ie); // Enable the appropriate registers


/* Setup filters, this filter will mark any message with ID 0x055 as a priority message */
TCAN4x5x_MCAN_SID_Filter SID_ID = {0};
SID_ID.SFT = TCAN4x5x_SID_SFT_CLASSIC; // SFT: Standard filter type. Configured as a classic filter
SID_ID.SFEC = TCAN4x5x_SID_SFEC_PRIORITYSTORERX0; // Standard filter element configuration, store it in RX fifo 0 as a priority message
SID_ID.SFID1 = 0x055; // SFID1 (Classic mode Filter)
SID_ID.SFID2 = 0x7FF; // SFID2 (Classic mode Mask)
TCAN4x5x_MCAN_WriteSIDFilter(0, &SID_ID); // Write to the MRAM


/* Store ID 0x12345678 as a priority message */
TCAN4x5x_MCAN_XID_Filter XID_ID = {0};
XID_ID.EFT = TCAN4x5x_XID_EFT_CLASSIC; // EFT
XID_ID.EFEC = TCAN4x5x_XID_EFEC_PRIORITYSTORERX0; // EFEC
XID_ID.EFID1 = 0x12345678; // EFID1 (Classic mode filter)
XID_ID.EFID2 = 0x1FFFFFFF; // EFID2 (Classic mode mask)
TCAN4x5x_MCAN_WriteXIDFilter(0, &XID_ID); // Write to the MRAM

/* Configure the TCAN4550 Non-CAN-related functions */
TCAN4x5x_DEV_CONFIG devConfig = {0}; // Remember to initialize to 0, or you'll get random garbage!
devConfig.SWE_DIS = 0; // Keep Sleep Wake Error Enabled (it's a disable bit, not an enable)
devConfig.DEVICE_RESET = 0; // Not requesting a software reset
devConfig.WD_EN = 0; // Watchdog disabled
devConfig.nWKRQ_CONFIG = 0; // Mirror INH function (default)
devConfig.INH_DIS = 0; // INH enabled (default)
devConfig.GPIO1_GPO_CONFIG = TCAN4x5x_DEV_CONFIG_GPO1_MCAN_INT1; // MCAN nINT 1 (default)
devConfig.FAIL_SAFE_EN = 0; // Failsafe disabled (default)
devConfig.GPIO1_CONFIG = TCAN4x5x_DEV_CONFIG_GPIO1_CONFIG_GPO; // GPIO set as GPO (Default)
devConfig.WD_ACTION = TCAN4x5x_DEV_CONFIG_WDT_ACTION_nINT; // Watchdog set an interrupt (default)
devConfig.WD_BIT_RESET = 0; // Don't reset the watchdog
devConfig.nWKRQ_VOLTAGE = 0; // Set nWKRQ to internal voltage rail (default)
devConfig.GPO2_CONFIG = TCAN4x5x_DEV_CONFIG_GPO2_NO_ACTION; // GPO2 has no behavior (default)
devConfig.CLK_REF = 1; // Input crystal is a 40 MHz crystal (default)
devConfig.WAKE_CONFIG = TCAN4x5x_DEV_CONFIG_WAKE_BOTH_EDGES;// Wake pin can be triggered by either edge (default)
TCAN4x5x_Device_Configure(&devConfig); // Configure the device with the above configuration

TCAN4x5x_Device_SetMode(TCAN4x5x_DEVICE_MODE_NORMAL); // Set to normal mode, since configuration is done. This line turns on the transceiver

TCAN4x5x_MCAN_ClearInterruptsAll(); // Resets all MCAN interrupts (does NOT include any SPIERR interrupts)
}

Best Regards,
Amy

  • Hi Amy,

    Can you please let us know what is connected on the CAN lines (CANH and CANL)?  You should typically have two 120-Ohm resistances, one on each side of the cable, placed between CANH and CANL.  From the waveforms it looks like this might not be present.  You would also generally need another CAN device to communicate with.  Otherwise, at the end of a frame the TCAN4550 will not receive an "acknowledgement" and may consider the frame transmission in error.

    Regards,
    Max