HB_ECLK_INVALID
HB_ECLK_INVALID, HB_ECLK_1, HB_ECLK_2, HB_ECLK_INVALID,
HB_ECLK_4, HB_ECLK_INVALID, HB_ECLK_6, HB_ECLK_INVALID,
(hb_eclk[new_divisor] == HB_ECLK_INVALID)) {