pulsesensor stm32f103程序

以下是Pulse Sensor的STM32F103程序示例：

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "stm32f1xx_hal.h"

// OLED screen dimensions
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32

// OLED screen I2C address
#define OLED_ADDR   0x3C

// Pulse sensor output pin
#define PULSE_PIN   PA0

// OLED display instance
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Global variables
volatile int BPM;
volatile int Signal;
volatile bool Pulse;

// Interrupt service routine for Pulse Sensor
void ISR_Pulse_Sensor(void)
{
  static unsigned long firstBeat, secondBeat, lastBeat;
  static int rate[10];
  static unsigned long sampleCounter = 0;
  static float beatsPerMinute;
  static int beatAvg = 0;

  // Calculate the time between beats in milliseconds
  Signal = analogRead(PULSE_PIN);
  sampleCounter += millis() - lastBeat;
  lastBeat = millis();

  int N = sampleCounter - lastBeat + firstBeat;
  if (Signal < 1000 && N > 250) {
    // First beat
    if (!firstBeat) {
      firstBeat = N;
      return;
    }
    // Second beat
    if (!secondBeat) {
      secondBeat = N;
      beatAvg = (firstBeat + secondBeat) / 2;
      beatsPerMinute = 60000 / beatAvg;
      BPM = int(beatsPerMinute);
      Pulse = true;
    }
    // Subsequent beats
    if (N < beatAvg) {
      rate[0] = N;
      int i;
      for (i = 1; i < 10; i++) {
        if (rate[i - 1] < 0) break;
        rate[i] = rate[i - 1] - 1;
      }
      rate[i] = N;
      beatAvg = 0;
      for (i = 0; i < 10; i++) {
        beatAvg += rate[i];
      }
      beatAvg /= 10;
      beatsPerMinute = 60000 / beatAvg;
      BPM = int(beatsPerMinute);
      Pulse = true;
    }
  }

  if (N > 2500) {
    sampleCounter = 0;
    firstBeat = 0;
    secondBeat = 0;
    beatAvg = 0;
  }
}

// Setup function
void setup() {
  // Initialize OLED screen
  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.clearDisplay();

  // Initialize Pulse Sensor pin and interrupt
  pinMode(PULSE_PIN, INPUT);
  attachInterrupt(PULSE_PIN, ISR_Pulse_Sensor, RISING);

  // Set up timer interrupt for display refresh
  TIM_HandleTypeDef htim;
  htim.Instance = TIM2;
  htim.Init.Prescaler = 64000 - 1;
  htim.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim.Init.Period = 250 - 1;
  htim.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  HAL_TIM_Base_Init(&htim);
  HAL_TIM_Base_Start_IT(&htim);
}

// Main loop function
void loop() {
  // If a pulse has been detected, display the BPM value
  if (Pulse == true) {
    display.clearDisplay();
    display.setCursor(0, 0);
    display.setTextSize(2);
    display.setTextColor(SSD1306_WHITE);
    display.print(BPM);
    display.print(" BPM");
    display.display();
    Pulse = false;
  }
}

// Timer interrupt service routine for display refresh
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) {
  if (htim->Instance == TIM2) {
    display.display();
  }
}

该代码使用STM32F103芯片和Pulse Sensor模块来测量心率，并在OLED显示屏上显示心率值。ISR_Pulse_Sensor()是Pulse Sensor的中断服务例程，用于检测脉冲并计算心率。setup()函数负责初始化所需的硬件和中断。loop()函数在检测到脉冲时更新OLED显示屏。注意，该代码使用了HAL库而不是标准的Arduino库，因此需要进行相应的配置。