The HCTL-2001 is a CMOS ICs that performs the quadrature decoder, counter, and bus interface function. The HCTL-20XX family is designed to improve system performance in digital closed loop motion control systems and digital data input systems. It does this by shifting time intensive quadrature decoder functions to a cost effective hardware solution. The HCTL-20XX consists of a quadrature decoder logic, a binary up/down state counter, and an 8-bit bus interface. The use of Schmitt-triggered CMOS inputs and input noise filters allows reliable operation in noisy environments. The HCTL-2001 contains 12-bit counter and provides TLL/CMOS compatible tri-state output buffers. Operation is specified for a temperature range from 40 to +85C at clock frequencies up to 14MHz.