48 lines
1.7 KiB
Python
Executable file
48 lines
1.7 KiB
Python
Executable file
#!/usr/bin/env python3
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"""Toggle the USB relay via serial: ./relay 1|0|id [serial_port]."""
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import sys
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import serial
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DEFAULT_PORT = "/dev/cu.usbserial-2110"
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def main() -> int:
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if len(sys.argv) not in (2, 3) or sys.argv[1] not in ("0", "1", "id"):
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print(f"Usage: {sys.argv[0]} 0|1|id [serial_port]", file=sys.stderr)
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return 1
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command = sys.argv[1]
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serial_cmd = "?" if command == "id" else command
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port = sys.argv[2] if len(sys.argv) == 3 else DEFAULT_PORT
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try:
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# dtr/rts expliciet uit vóór open: voorkomt (of beperkt) de CH340
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# auto-reset (DTR->RST) bij het openen van de poort. pyserial 3.5
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# accepteert geen dtr=/rts= kwargs in de constructor, maar de
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# states worden wél geëerd door open().
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s = serial.Serial()
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s.port = port
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s.baudrate = 115200
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s.timeout = 2
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s.dtr = False
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s.rts = False
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s.open()
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except serial.SerialException as exc:
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print(f"ERROR: cannot open {port}: {exc}", file=sys.stderr)
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return 1
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try:
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# Als het board toch reset bij open: wacht op de boot-banner en
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# gooi die weg, zodat de reply niet vervuild raakt. Geen banner
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# binnen 2 s (timeout, readline geeft b"") = geen reset: door.
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s.readline()
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s.reset_input_buffer()
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s.write(serial_cmd.encode())
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s.flush()
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reply = s.readline().decode(errors="replace").strip()
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finally:
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s.close()
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if reply in ("ON", "OFF") or (command == "id" and reply.startswith("ID ")):
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print(reply)
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return 0
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print(f"ERROR: no valid reply from board (got {reply!r})", file=sys.stderr)
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return 1
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if __name__ == "__main__":
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sys.exit(main())
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