52 lines
1.8 KiB
C
52 lines
1.8 KiB
C
/*
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* can_bus.h — MCP2515 CAN bus wrapper for KL630 (J15 SPI connector)
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*
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* API mirrors bt_uart.h: both channels carry the same JSON payload.
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* BLE channel: bt_uart_send_json(json)
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* CAN channel: can_bus_send_json(json)
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*
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* The same JSON string {"class":"car","level":1} is transmitted on both
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* channels simultaneously from fire_json_async() in event_recorder.c.
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*
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* MCP2515 is classic CAN (max 8 bytes per frame). Long JSON strings are
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* split into sequential 8-byte frames automatically:
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* Frame N: bytes [N*8 .. N*8+7] of the JSON string (padded with 0x00)
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* The receiver reassembles by concatenating frames until a null byte.
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* If a CAN FD controller is fitted later, switch to single-frame send.
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*/
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#ifndef CAN_BUS_H
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#define CAN_BUS_H
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#include <stdint.h>
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/*
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* can_bus_init — open MCP2515 via SPI and start writer thread.
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* spidev : e.g. "/dev/spidev1.0"
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* can_speed_kbps: 250 (typical) or 125, 500, 1000
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* can_id : 11-bit standard frame ID for outbound frames
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* Returns 0 on success, -1 on error.
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*/
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int can_bus_init(const char *spidev, int can_speed_kbps, uint32_t can_id);
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/*
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* can_bus_send_json — non-blocking: enqueue a JSON string for CAN transmission.
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* Same signature as bt_uart_send_json(); call both from fire_json_async().
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* Long strings are split into multiple 8-byte CAN frames automatically.
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*/
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void can_bus_send_json(const char *json);
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/*
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* can_bus_send_control_cmd — send one classic-CAN control frame.
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* Frame format (compatible with bt_proc.c reference):
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* CAN ID : 0x75 (11-bit)
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* DLC : 8
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* DATA : [cmd, 0, 0, 0, 0, 0, 0, 0]
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*/
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void can_bus_send_control_cmd(uint8_t cmd);
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/* can_bus_close — drain queue, join writer thread, close SPI device. */
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void can_bus_close(void);
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#endif /* CAN_BUS_H */
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