74hc393 is a double 4-bit binary counter. Adopts double row 14-pin package, 14-pin Ⅴcc, 7-pin ground. The first set of counter pin functions, 2 pins clear zero, 3,5,6,7 pins are QA1, QB1, QC1, QD1 output, 2 pins input. The second set of counter pin function, 12 pin clear, 11,10,9,8 pin is QA2, QB2, QC2, QD2 output, 13 pin input.