BlackMark
82a31d4f16
The host tool was standard-library-only but POSIX-only with it: termios and select() bound the port layer, and importing termios failed outright on Windows, so the module could not even load there. Split Port into PosixPort (unchanged) and a WindowsPort over the Win32 serial API through ctypes, picked by os.name; every call site keeps the Port name. kernel32 only, so the standard-library constraint holds. Windows has no select() for a COM handle, so the read deadlines move into the driver as COMMTIMEOUTS, re-armed per read: read_available() ends on a gap longer than a USB-serial latency timer coalesces (16 ms on FTDI parts), read_exact() on the count or its deadline. Opening asserts DTR and RTS as a POSIX open does, so a board wiring DTR to reset still pulses it. A failed configuration closes the handle before raising - a COM handle is exclusive, and the leak met the next open as "Access is denied". Win32 takes any integer baud and a driver may accept one its hardware cannot produce (an FT232R reports back a baud of 3 and keeps the old divisor), so obvious nonsense is refused where termios' table would have. Tested against an ATmega328P on COM6: info, fuses, both memories programmed and verified, session reconnect, hand-over, the loader self-update, and the write guard on its own slot. test_planner runs on Windows now as well. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>