def correct_ttl(x):
    """mne expects 8bit channel. biosemi has 24 bit. go down to 16 and adjust
    >>> correct_ttl(np.array([16128],dtype='int64')) # first stim ch val
    np.array([0],dtype='int16')
    """
    return x.astype(np.int32) - 127**2 + 1
    v = x - 16128  #  np.log2(16128+256)==14
    v[v == 65536] = 0  # 65536==2**16
    return v
    
def add_stim_corrected(raw):
    """
    >>> raw = mne.io.read_raw_bdf('/Volumes/Hera/Raw/EEG/SPA/12192_20251024/12192_20251024_rest.bdf')
    >>> add_stim_corrected(raw)
    """
    raw.load_data()
    stim_raw = raw.pick_channels(["Status"]).get_data()
    info = mne.create_info(["StatusCorrected"], raw.info["sfreq"], ["stim"])
    stim_vals = correct_ttl(stim_raw[0]).reshape(stim_raw.shape)
    stim = mne.io.RawArray(stim_vals, info)
    raw.add_channels([stim], force_update_info=True)