用数码管记录开机次数，即每断电再上电一次，数码管显示数字加一，需要用到存储器，片内或片外存储可自行选择

实现该功能可以使用一个非易失性存储器（如EEPROM）和一个7段数码管。每次开机时，从EEPROM中读取上一次记录的开机次数并加1，然后将结果写回EEPROM，同时将结果显示在7段数码管上。

以下是一个基于Arduino的示例代码：

#include <EEPROM.h>

const int DISPLAY_PIN_A = 2;
const int DISPLAY_PIN_B = 3;
const int DISPLAY_PIN_C = 4;
const int DISPLAY_PIN_D = 5;
const int DISPLAY_PIN_E = 6;
const int DISPLAY_PIN_F = 7;
const int DISPLAY_PIN_G = 8;
const int DISPLAY_PIN_DP = 9;

const int EEPROM_ADDRESS = 0;
int bootCount = 0;

void setup() {
  pinMode(DISPLAY_PIN_A, OUTPUT);
  pinMode(DISPLAY_PIN_B, OUTPUT);
  pinMode(DISPLAY_PIN_C, OUTPUT);
  pinMode(DISPLAY_PIN_D, OUTPUT);
  pinMode(DISPLAY_PIN_E, OUTPUT);
  pinMode(DISPLAY_PIN_F, OUTPUT);
  pinMode(DISPLAY_PIN_G, OUTPUT);
  pinMode(DISPLAY_PIN_DP, OUTPUT);

  bootCount = EEPROM.read(EEPROM_ADDRESS); // Read boot count from EEPROM
  bootCount++; // Increment boot count
  EEPROM.write(EEPROM_ADDRESS, bootCount); // Write updated boot count to EEPROM
}

void loop() {
  displayNumber(bootCount); // Display boot count on 7-segment display
  delay(1000); // Wait for one second
}

void displayNumber(int number) {
  static const byte digitMap[10] = {
    B11111100, // 0
    B01100000, // 1
    B11011010, // 2
    B11110010, // 3
    B01100110, // 4
    B10110110, // 5
    B10111110, // 6
    B11100000, // 7
    B11111110, // 8
    B11110110  // 9
  };

  if (number < 0 || number > 9999) {
    return; // Invalid input
  }

  // Extract individual digits from number
  int thousands = number / 1000;
  int hundreds = (number % 1000) / 100;
  int tens = (number % 100) / 10;
  int units = number % 10;

  // Display thousands digit (if non-zero)
  if (thousands > 0) {
    digitalWrite(DISPLAY_PIN_A, HIGH);
  } else {
    digitalWrite(DISPLAY_PIN_A, LOW);
  }
  digitalWrite(DISPLAY_PIN_B, digitMap[thousands] & B00000001);
  digitalWrite(DISPLAY_PIN_C, digitMap[thousands] & B00000010);
  digitalWrite(DISPLAY_PIN_D, digitMap[thousands] & B00000100);
  digitalWrite(DISPLAY_PIN_E, digitMap[thousands] & B00001000);
  digitalWrite(DISPLAY_PIN_F, digitMap[thousands] & B00010000);
  digitalWrite(DISPLAY_PIN_G, digitMap[thousands] & B00100000);

  // Display hundreds digit (if non-zero)
  if (hundreds > 0 || thousands > 0) {
    digitalWrite(DISPLAY_PIN_DP, LOW);
  } else {
    digitalWrite(DISPLAY_PIN_DP, HIGH);
  }
  digitalWrite(DISPLAY_PIN_B, digitMap[hundreds] & B00000001);
  digitalWrite(DISPLAY_PIN_C, digitMap[hundreds] & B00000010);
  digitalWrite(DISPLAY_PIN_D, digitMap[hundreds] & B00000100);
  digitalWrite(DISPLAY_PIN_E, digitMap[hundreds] & B00001000);
  digitalWrite(DISPLAY_PIN_F, digitMap[hundreds] & B00010000);
  digitalWrite(DISPLAY_PIN_G, digitMap[hundreds] & B00100000);

  // Display tens digit (if non-zero)
  if (tens > 0 || hundreds > 0 || thousands > 0) {
    digitalWrite(DISPLAY_PIN_DP, LOW);
  } else {
    digitalWrite(DISPLAY_PIN_DP, HIGH);
  }
  digitalWrite(DISPLAY_PIN_B, digitMap[tens] & B00000001);
  digitalWrite(DISPLAY_PIN_C, digitMap[tens] & B00000010);
  digitalWrite(DISPLAY_PIN_D, digitMap[tens] & B00000100);
  digitalWrite(DISPLAY_PIN_E, digitMap[tens] & B00001000);
  digitalWrite(DISPLAY_PIN_F, digitMap[tens] & B00010000);
  digitalWrite(DISPLAY_PIN_G, digitMap[tens] & B00100000);

  // Display units digit
  digitalWrite(DISPLAY_PIN_DP, LOW);
  digitalWrite(DISPLAY_PIN_B, digitMap[units] & B00000001);
  digitalWrite(DISPLAY_PIN_C, digitMap[units] & B00000010);
  digitalWrite(DISPLAY_PIN_D, digitMap[units] & B00000100);
  digitalWrite(DISPLAY_PIN_E, digitMap[units] & B00001000);
  digitalWrite(DISPLAY_PIN_F, digitMap[units] & B00010000);
  digitalWrite(DISPLAY_PIN_G, digitMap[units] & B00100000);
}

这个代码使用了一个名为`displayNumber`的函数，它将一个整数显示在7段数码管上。它还使用了一个名为`EEPROM`的库来读写EEPROM。您需要将7段数码管连接到Arduino引脚2到9，并将EEPROM连接到I2C总线上（如果使用I2C EEPROM）。请注意，这个代码只支持显示4位数以内的整数，如果需要显示更大的数字，需要相应地修改代码。