I want to do is a timer, when manually set the time increases, 10 to 6 when carry upwards, but the points when considering a borrow ten also becomes 6 a moment, so I add BON to judge circuit, if into 6 BON to 0 will not carry up, when using function really found BON and LDN signal has been to 1, but ten have been preset for 6, BON and LDN signal has become a 0, but the show has been to 1, why is this