FlexCAN driver

Collaboration diagram for FlexCAN driver:

This section describes the programming interface of the FlexCAN driver. The FlexCAN driver configures FlexCAN module, provides a functional and transactional interfaces to build the FlexCAN application.

Function groups

FLEXCAN Initialization and De-initialization

This function group initializes a default configuration structure for the FlexCAN module, initializes the FlexCAN module with a given configuration, resets, and de-initializes the FlexCAN module.

FlexCAN Configuration

This function group configures the FlexCAN module including the timing characteristic, transmit/receive message buffer, receive FIFO and Global/Individual masks for both receive message buffer and receive FIFO.

FlexCAN Basic Operation

This function group enables/disables the FlexCAN module, FlexCAN module interrupt, and FlexCAN message buffer interrupt and DMA. It also gets the receive FIFO head address for the receive FIFO DMA transfer.

FlexCAN Transfer Operation

This function group controls the transfer action including writing the transfer message buffer, reading the receive message buffer, and reading the receive FIFO.

FlexCAN Status Operation

This function group gets/clears the FlexCAN module status the FlexCAN message buffer/receive FIFO status.

FlexCAN Block Transfer Operation

This function group transfers a block of data, gets the transfer status, and aborts the transfer.

Typical use case

Message Buffer Send Operation

flexcan_config_t flexcanConfig;
flexcan_frame_t txFrame;

/* Init FlexCAN module. */
FLEXCAN_GetDefaultConfig(&flexcanConfig);
FLEXCAN_Init(EXAMPLE_CAN, &flexcanConfig);

/* Enable FlexCAN module. */
FLEXCAN_Enable(EXAMPLE_CAN, true);

/* Sets up the transmit message buffer. */
FLEXCAN_SetTxMbConfig(EXAMPLE_CAN, TX_MESSAGE_BUFFER_INDEX, true);

/* Prepares the transmit frame for sending. */
txFrame.format = KFLEXCAN_FrameFormatStandard;
txFrame.type   = KFLEXCAN_FrameTypeData;
txFrame.id     = FLEXCAN_ID_STD(0x123);
txFrame.length = 8;
txFrame.dataWord0 = CAN_WORD0_DATA_BYTE_0(0x11) |
                    CAN_WORD0_DATA_BYTE_1(0x22) |
                    CAN_WORD0_DATA_BYTE_2(0x33) |
                    CAN_WORD0_DATA_BYTE_3(0x44);
txFrame.dataWord1 = CAN_WORD1_DATA_BYTE_4(0x55) |
                    CAN_WORD1_DATA_BYTE_5(0x66) |
                    CAN_WORD1_DATA_BYTE_6(0x77) |
                    CAN_WORD1_DATA_BYTE_7(0x88);
/* Writes a transmit message buffer to send a CAN Message. */
FLEXCAN_WriteTxMb(EXAMPLE_CAN, TX_MESSAGE_BUFFER_INDEX, &txFrame);

/* Waits until the transmit message buffer is empty. */
while (!FLEXCAN_GetMbStatusFlags(EXAMPLE_CAN, 1 << TX_MESSAGE_BUFFER_INDEX));

/* Cleans the transmit message buffer empty status. */
FLEXCAN_ClearMbStatusFlags(EXAMPLE_CAN, 1 << TX_MESSAGE_BUFFER_INDEX);

Message Buffer Receive Operation

flexcan_config_t flexcanConfig;
flexcan_frame_t rxFrame;

/* Initializes the FlexCAN module. */
FLEXCAN_GetDefaultConfig(&flexcanConfig);
FLEXCAN_Init(EXAMPLE_CAN, &flexcanConfig);

/* Enables the FlexCAN module. */
FLEXCAN_Enable(EXAMPLE_CAN, true);

/* Sets up the receive message buffer. */
mbConfig.format    = KFLEXCAN_FrameFormatStandard;
mbConfig.type      = KFLEXCAN_FrameTypeData;
mbConfig.id        = FLEXCAN_ID_STD(0x123);
FLEXCAN_SetRxMbConfig(EXAMPLE_CAN, RX_MESSAGE_BUFFER_INDEX, &mbConfig, true);

/* Waits until the receive message buffer is full. */
while (!FLEXCAN_GetMbStatusFlags(EXAMPLE_CAN, 1 << RX_MESSAGE_BUFFER_INDEX));

/* Reads the received message from the receive message buffer. */
FLEXCAN_ReadRxMb(EXAMPLE_CAN, RX_MESSAGE_BUFFER_INDEX, &rxFrame);

/* Cleans the receive message buffer full status. */
FLEXCAN_ClearMbStatusFlags(EXAMPLE_CAN, 1 << RX_MESSAGE_BUFFER_INDEX);

Receive FIFO Operation

uint32_t rxFifoFilter[] = {FLEXCAN_RX_FIFO_STD_FILTER_TYPE_A(0x321, 0, 0),
                           FLEXCAN_RX_FIFO_STD_FILTER_TYPE_A(0x321, 1, 0),
                           FLEXCAN_RX_FIFO_STD_FILTER_TYPE_A(0x123, 0, 0),
                           FLEXCAN_RX_FIFO_STD_FILTER_TYPE_A(0x123, 1, 0)};

flexcan_config_t flexcanConfig;
flexcan_frame_t rxFrame;

/* Initializes the FlexCAN module. */
FLEXCAN_GetDefaultConfig(&flexcanConfig);
FLEXCAN_Init(EXAMPLE_CAN, &flexcanConfig);

/* Enables the FlexCAN module. */
FLEXCAN_Enable(EXAMPLE_CAN, true);

/* Sets up the receive FIFO. */
rxFifoConfig.idFilterTable = rxFifoFilter;
rxFifoConfig.idFilterType  = KFLEXCAN_RxFifoFilterTypeA;
rxFifoConfig.idFilterNum   = sizeof(rxFifoFilter) / sizeof(rxFifoFilter[0]);
rxFifoConfig.priority      = KFLEXCAN_RxFifoPrioHigh;
FlEXCAN_SetRxFifoConfig(EXAMPLE_CAN, &rxFifoConfig, true);

/* Waits until the receive FIFO becomes available. */
while (!FLEXCAN_GetMbStatusFlags(EXAMPLE_CAN, KFLEXCAN_RxFifoFrameAvlFlag));

/* Reads the message from the receive FIFO. */
FlEXCAN_ReadRxFifo(EXAMPLE_CAN, &rxFrame);

/* Cleans the receive FIFO available status. */
FLEXCAN_ClearMbStatusFlags(EXAMPLE_CAN, KFLEXCAN_RxFifoFrameAvlFlag);