单片机源程序如下:

/** file main.cpp ******************************************************

*

* Project: STM32F103C8T6+MAX30102

* Edited by Anning

* ------------------------------------------------------------------------- */

/*******************************************************************************

* Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.

*

/*!mainpage Main Page

*

* section intro_sec Introduction

*

* This is the code documentation for the MAXREFDES117# subsystem reference design.

*

*  The Files page contains the File List page and the Globals page.

*

*  The Globals page contains the Functions, Variables, and Macros sub-pages.

*

* image html MAXREFDES117_Block_Diagram.png "MAXREFDES117# System Block Diagram"

*

* image html MAXREFDES117_firmware_Flowchart.png "MAXREFDES117# Firmware Flowchart"

*

*/

#include "stm32f103c8t6.h"

#include "mbed.h"

#include "algorithm.h"

#include "MAX30102.h"

#define MAX_BRIGHTNESS 255

uint32_t aun_ir_buffer[500]; //IR LED sensor data

int32_t n_ir_buffer_length;    //data length

uint32_t aun_red_buffer[500];    //Red LED sensor data

int32_t n_sp02; //SPO2 value

int8_t ch_spo2_valid;   //indicator to show if the SP02 calculation is valid

int32_t n_heart_rate;   //heart rate value

int8_t  ch_hr_valid;    //indicator to show if the heart rate calculation is valid

uint8_t uch_dummy;

Serial pc(SERIAL_TX, SERIAL_RX);    //initializes the serial port, TX-PA2, RX-PA3

PwmOut pwmled(PB_3);  //initializes the pwm output PB3 that connects to the LED

DigitalIn INT(PB_7);  //pin PB7 connects to the interrupt output pin of the MAX30102

DigitalOut led(PC_13); //PC13 connects to the on board user LED

// the setup routine runs once when you press reset:

int main() {

uint32_t un_min, un_max, un_prev_data;  //variables to calculate the on-board LED brightness that reflects the heartbeats

int i;

int32_t n_brightness;

float f_temp;

maxim_max30102_reset(); //resets the MAX30102

// initialize serial communication at 115200 bits per second:

pc.baud(115200);

pc.format(8,SerialBase::None,1);

wait(1);

//read and clear status register

maxim_max30102_read_reg(0,&uch_dummy);

//wait until the user presses a key

//    while(pc.readable()==0)

//    {

//        pc.printf("x1B[2J");  //clear terminal program screen

//        pc.printf("Press any key to start conversionnr");

//        wait(1);

//    }

//    uch_dummy=getchar();

maxim_max30102_init();  //initializes the MAX30102

n_brightness=0;

un_min=0x3FFFF;

un_max=0;

n_ir_buffer_length=500; //buffer length of 100 stores 5 seconds of samples running at 100sps

//read the first 500 samples, and determine the signal range

for(i=0;i{

while(INT.read()==1);   //wait until the interrupt pin asserts

maxim_max30102_read_fifo((aun_red_buffer+i), (aun_ir_buffer+i));  //read from MAX30102 FIFO

if(un_min>aun_red_buffer[i])

un_min=aun_red_buffer[i];    //update signal min

if(un_maxun_max=aun_red_buffer[i];    //update signal max

pc.printf("red=");

pc.printf("%i", aun_red_buffer[i]);

pc.printf(", ir=");

pc.printf("%inr", aun_ir_buffer[i]);

}

un_prev_data=aun_red_buffer[i];

//calculate heart rate and SpO2 after first 500 samples (first 5 seconds of samples)

maxim_heart_rate_and_oxygen_saturation(aun_ir_buffer, n_ir_buffer_length, aun_red_buffer, &n_sp02, &ch_spo2_valid, &n_heart_rate, &ch_hr_valid);

//Continuously taking samples from MAX30102.  Heart rate and SpO2 are calculated every 1 second

while(1)

{

i=0;

un_min=0x3FFFF;

un_max=0;

//dumping the first 100 sets of samples in the memory and shift the last 400 sets of samples to the top

for(i=100;i<500;i++)

{

aun_red_buffer[i-100]=aun_red_buffer[i];

aun_ir_buffer[i-100]=aun_ir_buffer[i];

//update the signal min and max

if(un_min>aun_red_buffer[i])

un_min=aun_red_buffer[i];

if(un_maxun_max=aun_red_buffer[i];

}

//take 100 sets of samples before calculating the heart rate.

for(i=400;i<500;i++)

{

un_prev_data=aun_red_buffer[i-1];

while(INT.read()==1);

maxim_max30102_read_fifo((aun_red_buffer+i), (aun_ir_buffer+i));

if(aun_red_buffer[i]>un_prev_data)//just to determine the brightness of LED according to the deviation of adjacent two AD data

{

f_temp=aun_red_buffer[i]-un_prev_data;

f_temp/=(un_max-un_min);

f_temp*=MAX_BRIGHTNESS;

n_brightness-=(int)f_temp;

if(n_brightness<0)

n_brightness=0;

}

else

{

f_temp=un_prev_data-aun_red_buffer[i];

f_temp/=(un_max-un_min);

f_temp*=MAX_BRIGHTNESS;

n_brightness+=(int)f_temp;

if(n_brightness>MAX_BRIGHTNESS)

n_brightness=MAX_BRIGHTNESS;

}

pwmled.write(1-(float)n_brightness/256);//pwm control led brightness

if(n_brightness<120)

led=1;

else

led=0;

//send samples and calculation result to terminal program through UART

pc.printf("red=");

pc.printf("%i", aun_red_buffer[i]);

pc.printf(", ir=");

pc.printf("%i", aun_ir_buffer[i]);

pc.printf(", HR=%i, ", n_heart_rate);

pc.printf("HRvalid=%i, ", ch_hr_valid);

pc.printf("SpO2=%i, ", n_sp02);

pc.printf("SPO2Valid=%inr", ch_spo2_valid);

}

maxim_heart_rate_and_oxygen_saturation(aun_ir_buffer, n_ir_buffer_length, aun_red_buffer, &n_sp02, &ch_spo2_valid, &n_heart_rate, &ch_hr_valid);

}

}