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| socketcan_dune_implementation [2019/10/11 17:05] – nikolal | socketcan_dune_implementation [2022/09/19 11:34] (current) – external edit 127.0.0.1 |
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| ===== Interface in DUNE ===== | ===== Interface in DUNE ===== |
| |
| Many DUNE tasks use an interface defined by ''%%IO::Handle%%'', and so does this CAN implementation. This means that there will be little difference between using CAN or Serial in DUNE. The biggest difference is that CAN uses addresses, and so must have functions to set and get these. The ''%%Poll::poll%%'' functionality also works, and makes it possible to read with timeout from the CAN bus. Reading it without checking will result in the task waiting until a CAN message is received. An example of reading with the DUNE SocketCAN implementation is: | Many DUNE tasks use an interface defined by ''%%IO::Handle%%'', and so does this CAN implementation. This means that there will be little difference between using CAN or Serial in DUNE. The biggest difference is that CAN uses addresses, and so must have functions to set and get these. The ''%%Poll::poll%%'' functionality also works, and makes it possible to read with timeout from the CAN bus. Reading it without checking will result in the task waiting until a CAN message is received. |
| | |
| | ==== Example of reading ==== |
| |
| if (Poll::poll(*m_can, 0.01)) { | if (Poll::poll(*m_can, 0.01)) { |
| } | } |
| | |
| Here, ''%%m_can_bfr%%'' is a char array that is used to store the data read from CAN. Writing to the CAN bus can be done like this: | Here, ''%%m_can_bfr%%'' is a char array that is used to store the data read from CAN. |
| | ==== Example of writing ==== |
| |
| m_can_bfr[0] = 0x4f; | m_can_bfr[0] = 0x4f; |
| m_can_bfr[4] = 0x72; | m_can_bfr[4] = 0x72; |
| | |
| m_can->setTXID(0x0000feab); | m_can->setTXID(0x0000feab); // If all messages is sent with the same ID, this only needs to be called once |
| m_can->write(m_can_bfr, 5); | m_can->write(m_can_bfr, 5); // Write 5 chars to CAN with the previously set ID |
| Here, ''%%m_can_bfr%%'' still is a char array. | Here, ''%%m_can_bfr%%'' still is a char array. |
| Thats it! | |
| | ==== Example of initializing a SocketCAN instance ==== |
| | The CAN implementation uses ''%%DUNE/System/Error.hpp%%'' to send errors when something goes wrong while initializing SocketCAN. Here is an example on how to initialize SocketCAN while catching eventual errors: |
| | try { |
| | m_can = new Hardware::SocketCAN(m_args.can_dev, SocketCAN::CAN_BASIC_EFF); |
| | } |
| | catch(std::runtime_error& e) { |
| | cri(DTR("Could not open CAN: %s"), e.what()); |
| | } |
| ===== Useful links ===== | ===== Useful links ===== |
| * [[https://www.kernel.org/doc/Documentation/networking/can.txt|Linux kernel documentation on CAN]] | * [[https://www.kernel.org/doc/Documentation/networking/can.txt|Linux kernel documentation on CAN]] |