Many data acquisition systems require both a visual display and a computer interface. The TC7135 from Microchip Technology is a 4-1/2 digit Analog-to-Digital converter (ADC) which can easily provide both of these functions. The TC7135’s multiplexed BCD outputs interface easily to low cost LED or LCD decoder/drivers, such as the TC7211A. Also, the TC7135’s data outputs simplify computer interfacing. This application note will present both the hardware and software required to interface the TC7135 to a microprocessor. The circuit was developed for a 6502µP and 6522 I/O port, but the design can easily be modified for other µPs and I/O ports. AN16 TC7135 Microprocessor Interface Low Roll-Over Error ...................................... ± 1 count Author: Wes Freeman, Microchip Technology, Inc. Valid Polarity at 000 reading (the + and ……