61 lines
1.9 KiB
Python
61 lines
1.9 KiB
Python
"""CAN485 DevBoard_V1 USB command and frame helpers (no GUI/serial dependency)."""
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from __future__ import annotations
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import re
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from dataclasses import dataclass
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FRAME_RE = re.compile(
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r"^\[\s*(\d+)\.(\d{3})\]\s+(?:(RS485)\s+)?"
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r"(EXT|STD)\s+0x([0-9A-Fa-f]+)\s+"
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r"(RTR\s+)?DLC=(\d)(?:\s+DATA=([0-9A-Fa-f ]*))?"
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)
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@dataclass(frozen=True, slots=True)
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class BoardFrame:
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timestamp: float
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extended: bool
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can_id: int
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data: bytes
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rtr: bool = False
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source: str = "CAN"
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def parse_frame_line(line: str) -> BoardFrame | None:
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match = FRAME_RE.match(line.strip())
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if match is None:
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return None
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seconds, millis, source, frame_type, raw_id, raw_rtr, raw_dlc, raw_data = match.groups()
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dlc = int(raw_dlc)
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data = bytes.fromhex(raw_data or "")
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rtr = bool(raw_rtr)
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if (not rtr and len(data) != dlc) or (rtr and data):
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return None
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extended = frame_type == "EXT"
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can_id = int(raw_id, 16)
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if can_id > (0x1FFFFFFF if extended else 0x7FF):
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return None
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return BoardFrame(int(seconds) + int(millis) / 1000.0, extended, can_id,
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data, rtr, source or "CAN")
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def command_transmit(frame: BoardFrame) -> bytes:
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if len(frame.data) > 8:
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raise ValueError("DLC cannot exceed 8")
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kind = "E" if frame.extended else "S"
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return f"T,{kind},{frame.can_id:X},{len(frame.data)},{frame.data.hex().upper()}\n".encode("ascii")
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def command_setup(*, can_bitrate: int = 500, rs485_baud: int = 512000,
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route: int = 3) -> tuple[bytes, ...]:
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if can_bitrate not in (25, 50, 100, 125, 250, 500, 800, 1000):
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raise ValueError("unsupported CAN bitrate")
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if not 1200 <= rs485_baud <= 4_000_000:
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raise ValueError("unsupported RS485 baud")
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if route not in range(4):
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raise ValueError("route must be 0..3")
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return (f"S{can_bitrate}\n".encode("ascii"), b"M0\n",
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f"B{rs485_baud}\n".encode("ascii"), f"Q{route}\n".encode("ascii"))
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