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C++趣味编程玩转物联网：用树莓派Pico实现一位数码管动态显示

news 2025/7/7 2:04:32

七段数码管是一种经典的电子显示器件，广泛应用于数字时钟、电子仪表等设备。本文将通过树莓派Pico开发板，介绍如何用C++代码控制一位七段数码管显示数字。作为一个嵌入式开发项目，这不仅是初学者理解数码管工作原理的好机会，也是C++开发者在硬件编程中的一个实践案例。

项目背景与目标

七段数码管的工作原理
七段数码管由七个LED组成（共阴极或共阳极设计），通过点亮不同的LED组合显示数字0-9。它是一种经济实用的显示解决方案，特别适合初学者学习电路控制和嵌入式编程。

项目目标
实现数码管动态显示数字9到0，通过延时循环显示数字序列，掌握数码管的基础控制方法以及C++程序与硬件的结合应用。

项目所需元件

树莓派Pico × 1
一位七段数码管（共阴极） × 1
220Ω电阻 × 8
面包板 × 1
公对母杜邦线若干
USB数据线 × 1

数码管的接线原理与注意事项

1. 共阴极数码管接线

共阴极设计：所有段的负极连接在一起，并接到Pico的GND引脚。要点亮某段LED，需将对应引脚设置为高电平。
限流保护：每个段LED需通过220Ω电阻连接，以避免过电流烧毁LED。

2. GPIO引脚分配

a 段：GP17
b 段：GP16
c 段：GP14
d 段：GP13
e 段：GP12
f 段：GP18
g 段：GP19
dp（小数点）：GP15

项目电路图和接线图

核心代码实现

以下是实现数字9到0动态显示的C++代码：

#include <Arduino.h>// 定义每个段的GPIO引脚
int a = 17, b = 16, c = 14, d = 13, e = 12, f = 18, g = 19, dp = 15;// 显示数字的函数
void digital_0() { digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, HIGH); digitalWrite(e, HIGH); digitalWrite(f, HIGH); digitalWrite(g, LOW); digitalWrite(dp, LOW); }
void digital_1() { digitalWrite(a, LOW); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, LOW); digitalWrite(e, LOW); digitalWrite(f, LOW); digitalWrite(g, LOW); digitalWrite(dp, LOW); }
void digital_2() { digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, LOW); digitalWrite(d, HIGH); digitalWrite(e, HIGH); digitalWrite(f, LOW); digitalWrite(g, HIGH); digitalWrite(dp, LOW); }
void digital_3() { digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, HIGH); digitalWrite(f, LOW); digitalWrite(e, LOW); digitalWrite(dp, LOW); digitalWrite(g, HIGH); }
void digital_4() { digitalWrite(a, LOW); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, LOW); digitalWrite(e, LOW); digitalWrite(f, HIGH); digitalWrite(dp, LOW); digitalWrite(g, HIGH); }
void digital_5() { digitalWrite(a, HIGH); digitalWrite(b, LOW); digitalWrite(c, HIGH); digitalWrite(d, HIGH); digitalWrite(e, LOW); digitalWrite(f, HIGH); digitalWrite(dp, LOW); digitalWrite(g, HIGH); }
void digital_6() { digitalWrite(a, HIGH); digitalWrite(b, LOW); digitalWrite(c, HIGH); digitalWrite(d, HIGH); digitalWrite(e, HIGH); digitalWrite(f, HIGH); digitalWrite(dp, LOW); digitalWrite(g, HIGH); }
void digital_7() { digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, LOW); digitalWrite(e, LOW); digitalWrite(f, LOW); digitalWrite(dp, LOW); digitalWrite(g, LOW); }
void digital_8() { digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, HIGH); digitalWrite(e, HIGH); digitalWrite(f, HIGH); digitalWrite(dp, LOW); digitalWrite(g, HIGH); }
void digital_9() { digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, HIGH); digitalWrite(d, HIGH); digitalWrite(e, LOW); digitalWrite(f, HIGH); digitalWrite(dp, LOW); digitalWrite(g, HIGH); }void setup() {for (int i = 12; i <= 19; i++) {pinMode(i, OUTPUT); // 将GPIO 12-19设置为输出模式}
}void loop() {digital_9(); delay(1000); digital_8(); delay(1000); digital_7(); delay(1000);digital_6(); delay(1000); digital_5(); delay(1000); digital_4(); delay(1000);digital_3(); delay(1000); digital_2(); delay(1000); digital_1(); delay(1000);digital_0(); delay(1000);
}