Add Berger LFP BLE command notes and client

tools/berger_frame.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+"""Build Berger/JBD BLE frames observed in the Android app."""
+
+from __future__ import annotations
+
+import argparse
+
+
+def checksum(command: int, payload: bytes = b"") -> int:
+    """JBD two's-complement checksum over command, length, and payload."""
+    total = (command + len(payload) + sum(payload)) & 0xFFFF
+    return ((total ^ 0xFFFF) + 1) & 0xFFFF
+
+
+def frame(mode: int, command: int, payload: bytes = b"") -> bytes:
+    check = checksum(command, payload)
+    return bytes([0xDD, mode, command, len(payload), *payload, check >> 8, check & 0xFF, 0x77])
+
+
+def read_frame(command: int) -> bytes:
+    return frame(0xA5, command)
+
+
+def write_frame(command: int, payload: bytes) -> bytes:
+    return frame(0x5A, command, payload)
+
+
+def name_frame(command: int, payload: bytes = b"") -> bytes:
+    check = (command + len(payload) + sum(payload)) & 0xFF
+    return bytes([0xFF, 0xAA, command, len(payload), *payload, check])
+
+
+def parse_hex_bytes(value: str) -> bytes:
+    clean = value.replace(" ", "").replace(":", "")
+    return bytes.fromhex(clean)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    sub = parser.add_subparsers(dest="cmd", required=True)
+
+    p_read = sub.add_parser("read")
+    p_read.add_argument("command", type=lambda x: int(x, 0))
+
+    p_write = sub.add_parser("write")
+    p_write.add_argument("command", type=lambda x: int(x, 0))
+    p_write.add_argument("payload_hex", nargs="?", default="")
+
+    p_name = sub.add_parser("name")
+    p_name.add_argument("value")
+
+    args = parser.parse_args()
+    if args.cmd == "read":
+        print(read_frame(args.command).hex().upper())
+    elif args.cmd == "write":
+        print(write_frame(args.command, parse_hex_bytes(args.payload_hex)).hex().upper())
+    elif args.cmd == "name":
+        print(name_frame(0x07, args.value.encode("ascii")).hex().upper())
+
+
+if __name__ == "__main__":
+    main()