{"type":"doc","content":[{"type":"paragraph","content":[{"text":"This doc is all about how to set up a MAVLink forwarding channel in SSM and how to use it. ","type":"text"}]},{"type":"heading","attrs":{"level":2},"content":[{"text":"IOC config","type":"text"}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"Key Parameter Setting","type":"text"}]},{"type":"paragraph","content":[{"text":"The default UART setting works.","type":"text"}]},{"type":"panel","attrs":{"panelType":"warning"},"content":[{"type":"paragraph","content":[{"text":"The Baud Rate of the UART has to match with the Baud Rate that Pixhawk receives.","type":"text"}]},{"type":"paragraph","content":[{"text":"Either change the baud rate of UART or serial setting on Mission Planner","type":"text"}]}]},{"type":"paragraph"},{"type":"heading","attrs":{"level":4},"content":[{"text":"DMA Setting","type":"text"}]},{"type":"bulletList","content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Enable both rx DMA line for the uart used","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Keep the DMA to be “Normal“","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"Enable uart global interrupt in NVIC ","type":"text"}]}]}]},{"type":"heading","attrs":{"level":4},"content":[{"text":"Explanation ","type":"text"}]},{"type":"bulletList","content":[{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"When passing the mavlink message from one place to the other place. We need to initialize two class objects.","type":"text"}]}]},{"type":"listItem","content":[{"type":"paragraph","content":[{"text":"In the actual implementation, we may need to initialize three objects. One for the air side, one for the ground side, one for the jetson.","type":"text"}]}]}]},{"type":"paragraph"},{"type":"heading","attrs":{"level":2},"content":[{"text":"Struct","type":"text"}]},{"type":"paragraph","content":[{"text":"All the struct types are included in the MAVLink library.","type":"text"}]},{"type":"paragraph","content":[{"text":"The output data type – mavlink_message_t","type":"text"}]},{"type":"codeBlock","content":[{"text":"typedef struct __mavlink_message {\n\tuint16_t checksum; ///< sent at end of packet\n\tuint8_t magic; ///< protocol magic marker\n\tuint8_t len; ///< Length of payload\n\tuint8_t incompat_flags; ///< flags that must be understood\n\tuint8_t compat_flags; ///< flags that can be ignored if not understood\n\tuint8_t seq; ///< Sequence of packet\n\tuint8_t sysid; ///< ID of message sender system/aircraft\n\tuint8_t compid; ///< ID of the message sender component\n\tuint32_t msgid:24; ///< ID of message in payload\n\tuint64_t payload64[(MAVLINK_MAX_PAYLOAD_LEN+MAVLINK_NUM_CHECKSUM_BYTES+7)/8];\n\tuint8_t ck[2]; ///< incoming checksum bytes\n\tuint8_t signature[MAVLINK_SIGNATURE_BLOCK_LEN];\n}) mavlink_message_t;","type":"text"}]},{"type":"paragraph"},{"type":"heading","attrs":{"level":2},"content":[{"text":"Methods","type":"text"}]},{"type":"codeBlock","content":[{"text":"class MAVLink {\n\tpublic:\n\n uint8_t rx_circular_buffer_ptr_[1000];\n CircularBuffer* rx_circular_buffer_;\n uint8_t raw_rx_msg_[RAW_MAVLINK_LENGTH];\n \n /* Constructor */\n\t\tMAVLink(UART_HandleTypeDef* uart_handle);\n ~MAVLink();\n\n\n /* \n\t\t\t@param - the passby parameter, return the new message\n\t\t\t@return - true if new message returned, false means no new message returned\n */\n bool readMessage(mavlink_message_t& message);\n\n /*\n \t @param - output mavlink message\n \t @return - none\n */\n void writeMessage(const mavlink_message_t output_message);\n \n\tprivate:\n UART_HandleTypeDef* uart_;\n};","type":"text"}]},{"type":"paragraph"}],"version":1}

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