Document BullTron BLE commands

tools/bulltron_frame.py

@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+"""Build BullTron/Daly-style BLE frames observed in the Android app."""
+
+from __future__ import annotations
+
+import argparse
+
+
+def crc16_modbus_swapped(hex_data: str) -> str:
+    data = bytes.fromhex(hex_data)
+    crc = 0xFFFF
+    for byte in data:
+        crc ^= byte
+        for _ in range(8):
+            if crc & 1:
+                crc = (crc >> 1) ^ 0xA001
+            else:
+                crc >>= 1
+    swapped = ((crc & 0xFF00) >> 8) | ((crc & 0x00FF) << 8)
+    return f"{swapped:04X}"
+
+
+def read_frame(start: int, count: int) -> str:
+    body = f"D203{start:04X}{count:04X}"
+    return body + crc16_modbus_swapped(body)
+
+
+def write_single_frame(register: int, value: int) -> str:
+    body = f"D206{register:04X}{value:04X}"
+    return body + crc16_modbus_swapped(body)
+
+
+def write_multi_frame(start: int, count: int, payload_hex: str) -> str:
+    payload = payload_hex.replace(" ", "").upper()
+    body = f"D210{start:04X}{count:04X}{payload}"
+    return body + crc16_modbus_swapped(body)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    sub = parser.add_subparsers(dest="cmd", required=True)
+
+    p_read = sub.add_parser("read")
+    p_read.add_argument("start", type=lambda x: int(x, 0))
+    p_read.add_argument("count", type=lambda x: int(x, 0))
+
+    p_write = sub.add_parser("write")
+    p_write.add_argument("register", type=lambda x: int(x, 0))
+    p_write.add_argument("value", type=lambda x: int(x, 0))
+
+    p_multi = sub.add_parser("write-multi")
+    p_multi.add_argument("start", type=lambda x: int(x, 0))
+    p_multi.add_argument("count", type=lambda x: int(x, 0))
+    p_multi.add_argument("payload_hex")
+
+    args = parser.parse_args()
+    if args.cmd == "read":
+        print(read_frame(args.start, args.count))
+    elif args.cmd == "write":
+        print(write_single_frame(args.register, args.value))
+    elif args.cmd == "write-multi":
+        print(write_multi_frame(args.start, args.count, args.payload_hex))
+
+
+if __name__ == "__main__":
+    main()