Single chip microcomputer scheme principle and its application single chip microcomputer interface technology, display and its interface, keyboard interface, D / a converter and its interface, a / D converter and its interface, printer interface, dial and voice interface, D / a converter and its interface, a / D converter and its interface, D / a converter and its ports, D / a converter, 51 single chip microcomputer and D / a interface, Principle of D / a converter: convert each input digital quantity into analog quantity according to its weight, and sum it through operational amplifier. According to Kirchhoff's law, the output form of D / a converter, voltage output, current output and output plus operational amplifier convert current into voltage. Interface form of D / a converter, parallel, bus interface, serial, serial port, input latch of D / a converter (parallel interface) no latch can be directly connected to P0, and a latch can be directly connected to P0. D / a converter performance index resolution: resolution refers to the change of analog output caused by unit digital quantity of D / a converter. One partner is defined as: full output analog quantity. Conversion accuracy: conversion accuracy refers to the large relative error between the actual analog output value of DAC and the theoretical value in the full range during full-scale calibration. Linearity: linearity refers to the large offset error between the actual conversion curve of DAC and the ideal straight line. Setup time: setup time is the time required for the output to reach the final value when the data changes to the full scale.