Example Summary

This example demonstrates using the CAN driver to transmit or receive a message for time synchronization with another SimpleLink™ device. This example is designed to be used with a second SimpleLink™ device which is also running this example.

Peripherals & Pin Assignments

When this project is built, the SysConfig tool will generate the TI-Driver configurations into the ti_drivers_config.c and ti_drivers_config.h files. Information on pins and resources used is present in both generated files. Additionally, the System Configuration file (*.syscfg) present in the project may be opened with SysConfig’s graphical user interface to determine pins and resources used.

BoosterPacks, Board Resources & Jumper Settings

This example requires two LaunchPads with an integrated CAN controller and two external CAN transceiver boards to communicate on the CAN bus.

The transceiver should be connected to the LaunchPad as follows:

LaunchPad Pin	CAN Transceiver Pin
BP.31 (DIO18)	RXD
BP.32 (DIO17)	TXD

Initialization and configuration of the CAN transceiver is not handled by this example and must be performed independently.

Before running the example, the CANL and CANH bus signals should be connected between the transceivers with the appropriate CAN bus termination.

For board specific jumper settings, resources and BoosterPack modifications, refer to the Board.html file.

If you’re using an IDE such as Code Composer Studio (CCS) or IAR, please refer to Board.html in your project directory for resources used and board-specific jumper settings.

The Board.html can also be found in your SDK installation:

<SDK_INSTALL_DIR>/source/ti/boards/<BOARD>

Example Usage

• Open a serial session (e.g. PuTTY, etc.) to the appropriate COM port.
  • The COM port can be determined via Device Manager in Windows or via ls /dev/tty* in Linux.

The connection should have the following settings:

    Baud-rate:  115200
    Data bits:       8
    Stop bits:       1
    Parity:       None
    Flow Control: None

• Run the example. CONFIG_GPIO_LED_0 turns ON to indicate driver initialization is complete.

• Once example is running on both LaunchPads, CAN messages can be transmitted from either LaunchPad to the other LaunchPad. Press either BTN-1 or BTN-2 to transmit a CAN message with a zero byte payload and a specific message ID.

  LaunchPad Button	CAN Message ID
  BTN-1	Time Sync ID (0x2)
  BTN-2	Non-Time Sync ID (0x3)

• When a message with the Time Sync ID is transmitted or received, the example will determine when the Start Of Frame (SOF) occurred and then toggle CONFIG_GPIO_LED_1 500us after the SOF. A logic analyzer can be connected to the CAN TXD/RXD and LED to measure the timing.

• The target will print any received CAN message details to the UART.

Sample UART output after pressing BTN-1 on the LaunchPad_1

LaunchPad_1 (Transmitter):

    CAN Time Sync ready.
    Press BTN-1 to send time sync msg or BTN-2 to send a regular msg...

    Sending time sync message...

    > Tx Finished. Cnt = 1

    > Tx Event. TXTS = 0x1814, SOF time = 0x024a29b2

LaunchPad_2 (Receiver):

    CAN Time Sync ready.
    Press BTN-1 to send time sync msg or BTN-2 to send a regular msg...

    > Time Sync msg Rx'ed. RXTS = 0xae8f, SOF time = 0x015c97b0

    RxMsg Cnt: 1, RxEvt Cnt: 1
    Msg ID: 0x2
    TS: 0xae8f
    CAN FD: 1
    DLC: 0
    BRS: 1
    ESI: 0
    Data[0]:

Sample UART output after pressing BTN-2 on the LaunchPad_1

LaunchPad_1 (Transmitter):

    Sending regular message...

    > Tx Finished. Cnt = 2

LaunchPad_2 (Receiver):

    RxMsg Cnt: 2, RxEvt Cnt: 2
    Msg ID: 0x3
    TS: 0x675f
    CAN FD: 1
    DLC: 0
    BRS: 1
    ESI: 0
    Data[0]:

Application Design Details

This application uses one thread, timeSyncTxThread , which blocks on a button press: BTN-1 for transmitting a message with the time sync ID or BTN-2 for transmitting a message with a regular ID.

An event callback, eventCallback, is registered with the CAN driver for handling various events. Notably, the reception of CAN messages (and associated Rx timestamps) and the notification of successful transmission of CAN messages with Event FIFO Control (EFC) bit set (and associated Tx timestamps). These timestamps are converted to system time and used to toggle a LED exactly 500us after the Start Of Frame occurs for the CAN time sync message.

FreeRTOS:

• Please view the FreeRTOSConfig.h header file for example configuration information.