Single-chip microcomputer high-precision analog quantity output method, device and equipment based on PWM waveform

Abstract

The invention provides a single-chip microcomputer high-precision analog quantity output method, device and equipment based on a PWM waveform. The method comprises the steps that the output frequencyof the PWM waveform is set to be A Hz; a voltage value U with millivolt as a unit is obtained; if the full-scale output value of the single-chip microcomputer is B volt, the B volt is converted into B*1000 millivolt, the B*1000 millivolt can be regarded as having B*1000 small sections B1 in one period T, and the duty ratio is the ratio of the voltage value U to the B*1000 small sections B1; when the PWM waveform is output at the output frequency, the PWM waveform can be regarded as that A small sections A1 are evenly distributed in the PWM waveform within one period T, the duty ratio requirement is met, the output frequency requirement is met at the same time, and in the PWM waveform, it is set that a high level exists within one period T, and the finally output PWM waveform is generated.The single-chip microcomputer realizes high-precision analog quantity output without adding a D / A chip, so that the cost of digital-to-analog conversion of the single-chip microcomputer is reduced, and the output analog quantity can be controlled to reach the precision of 1mV.

Description

technical field [0001] The invention relates to analog quantity output in digital-to-analog conversion, in particular to a single-chip microcomputer high-precision analog quantity output method, device and equipment based on PWM waveforms. Background technique [0002] Low-performance single-chip microcomputers such as 51 series are widely used because of their cheap price, but low-performance single-chip microcomputers do not have D / A function, so the existing low-performance single-chip microcomputers need to add a D / A chip when performing digital-to-analog conversion , Of course, the low-performance microcontroller can also control the output frequency through the internal timer, and output the analog quantity by outputting the PWM waveform. [0003] However, the maximum crystal oscillator frequency of the existing low-performance single-chip microcomputer is 16MHz, and its one machine cycle is 1 / 16us. After software calculation and processing, the maximum output frequen...

AI Technical Summary

Problems solved by technology

[0004] It can be seen that low-performance single-chip microcomputers need the cooperation of D / A chips to achieve high-precision analog output, and adding D / A chips to achieve analog output will undoubtedly increase the cost of digital-to-analog conversion, but only Relying on the timer in the single-chip microcomputer to control the output frequency and output PWM waveform, the output analog quantity cannot reach the accuracy of 1mV

Images