hi, minh dang tim hieu con pic8f4431, co dieu minh cam board de thu thi tat ca chan chip deu 1,5v chu ko ve 0 hoac 5v, minh dung thach anh 4m, cap nguon 5v tu nguon may tinh vao 2 cap chan nguon chip roi, ke ca ngan ctac reset roi ma van ko xu ly duoc chan chip, ke ca khi viet chuong trinh nap dua chan chip ve 0 hoac 1 deu ko dc. ban o hn hay sg?