代碼:

1. #include "stm32f103c8t6.h"
   
2. #include "mbed.h"
   
3. #include "algorithm.h"
   
4. #include "MAX30102.h"
   
5. 
   
6. #define MAX_BRIGHTNESS 255
   
7. 
   
8. uint32_t aun_ir_buffer[500]; //IR LED sensor data
   
9. int32_t n_ir_buffer_length;    //data length
   
10. uint32_t aun_red_buffer[500];    //Red LED sensor data
    
11. int32_t n_sp02; //SPO2 value
    
12. int8_t ch_spo2_valid;   //indicator to show if the SP02 calculation is valid
    
13. int32_t n_heart_rate;   //heart rate value
    
14. int8_t  ch_hr_valid;    //indicator to show if the heart rate calculation is valid
    
15. uint8_t uch_dummy;
    
16. 
    
17. Serial pc(SERIAL_TX, SERIAL_RX);    //initializes the serial port, TX-PA2, RX-PA3
    
18. 
    
19. PwmOut pwmled(PB_3);  //initializes the pwm output PB3 that connects to the LED
    
20. DigitalIn INT(PB_7);  //pin PB7 connects to the interrupt output pin of the MAX30102
    
21. DigitalOut led(PC_13); //PC13 connects to the on board user LED
    
22. 
    
23. 
    
24. // the setup routine runs once when you press reset:
    
25. int main() {
    
26.     uint32_t un_min, un_max, un_prev_data;  //variables to calculate the on-board LED brightness that reflects the heartbeats
    
27.     int i;
    
28.     int32_t n_brightness;
    
29.     float f_temp;
    
30. 
    
31.     maxim_max30102_reset(); //resets the MAX30102
    
32.     // initialize serial communication at 115200 bits per second:
    
33.     pc.baud(115200);
    
34.     pc.format(8,SerialBase::None,1);
    
35.     wait(1);
    
36. 
    
37.     //read and clear status register
    
38.     maxim_max30102_read_reg(0,&uch_dummy);
    
39. 
    
40.     //wait until the user presses a key
    
41. //    while(pc.readable()==0)
    
42. //    {
    
43. //        pc.printf("\x1B[2J");  //clear terminal program screen
    
44. //        pc.printf("Press any key to start conversion\n\r");
    
45. //        wait(1);
    
46. //    }
    
47. //    uch_dummy=getchar();
    
48. 
    
49.     maxim_max30102_init();  //initializes the MAX30102
    
50. 
    
51. 
    
52.     n_brightness=0;
    
53.     un_min=0x3FFFF;
    
54.     un_max=0;
    
55. 
    
56.     n_ir_buffer_length=500; //buffer length of 100 stores 5 seconds of samples running at 100sps
    
57. 
    
58.     //read the first 500 samples, and determine the signal range
    
59.     for(i=0;i<n_ir_buffer_length;i++)
    
60.     {
    
61.         while(INT.read()==1);   //wait until the interrupt pin asserts
    
62. 
    
63.         maxim_max30102_read_fifo((aun_red_buffer+i), (aun_ir_buffer+i));  //read from MAX30102 FIFO
    
64. 
    
65.         if(un_min>aun_red_buffer[i])
    
66.             un_min=aun_red_buffer[i];    //update signal min
    
67.         if(un_max<aun_red_buffer[i])
    
68.             un_max=aun_red_buffer[i];    //update signal max
    
69.         pc.printf("red=");
    
70.         pc.printf("%i", aun_red_buffer[i]);
    
71.         pc.printf(", ir=");
    
72.         pc.printf("%i\n\r", aun_ir_buffer[i]);
    
73.     }
    
74.     un_prev_data=aun_red_buffer[i];
    
75. 
    
76. 
    
77.     //calculate heart rate and SpO2 after first 500 samples (first 5 seconds of samples)
    
78.     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);
    
79. 
    
80.     //Continuously taking samples from MAX30102.  Heart rate and SpO2 are calculated every 1 second
    
81.     while(1)
    
82.     {
    
83.         i=0;
    
84.         un_min=0x3FFFF;
    
85.         un_max=0;
    
86. 
    
87.         //dumping the first 100 sets of samples in the memory and shift the last 400 sets of samples to the top
    
88.         for(i=100;i<500;i++)
    
89.         {
    
90.             aun_red_buffer[i-100]=aun_red_buffer[i];
    
91.             aun_ir_buffer[i-100]=aun_ir_buffer[i];
    
92. 
    
93.             //update the signal min and max
    
94.             if(un_min>aun_red_buffer[i])
    
95.             un_min=aun_red_buffer[i];
    
96.             if(un_max<aun_red_buffer[i])
    
97.             un_max=aun_red_buffer[i];
    
98.         }
    
99. 
    
100.         //take 100 sets of samples before calculating the heart rate.
     
101.         for(i=400;i<500;i++)
     
102.         {
     
103.             un_prev_data=aun_red_buffer[i-1];
     
104.             while(INT.read()==1);
     
105.             maxim_max30102_read_fifo((aun_red_buffer+i), (aun_ir_buffer+i));
     
106. 
     
107.             if(aun_red_buffer[i]>un_prev_data)//just to determine the brightness of LED according to the deviation of adjacent two AD data
     
108.             {
     
109.                 f_temp=aun_red_buffer[i]-un_prev_data;
     
110.                 f_temp/=(un_max-un_min);
     
111.                 f_temp*=MAX_BRIGHTNESS;
     
112.                 n_brightness-=(int)f_temp;
     
113.                 if(n_brightness<0)
     
114.                     n_brightness=0;
     
115.             }
     
116.             else
     
117.             {
     
118.                 f_temp=un_prev_data-aun_red_buffer[i];
     
119.                 f_temp/=(un_max-un_min);
     
120.                 f_temp*=MAX_BRIGHTNESS;
     
121.                 n_brightness+=(int)f_temp;
     
122.                 if(n_brightness>MAX_BRIGHTNESS)
     
123.                     n_brightness=MAX_BRIGHTNESS;
     
124.             }
     
125. 
     
126.             pwmled.write(1-(float)n_brightness/256);//pwm control led brightness
     
127.                                                 if(n_brightness<120)
     
128.                                                         led=1;
     
129.                                                 else
     
130.                                                         led=0;
     
131. 
     
132.             //send samples and calculation result to terminal program through UART
     
133.             pc.printf("red=");
     
134.             pc.printf("%i", aun_red_buffer[i]);
     
135.             pc.printf(", ir=");
     
136.             pc.printf("%i", aun_ir_buffer[i]);
     
137.             pc.printf(", HR=%i, ", n_heart_rate);
     
138.             pc.printf("HRvalid=%i, ", ch_hr_valid);
     
139.             pc.printf("SpO2=%i, ", n_sp02);
     
140.             pc.printf("SPO2Valid=%i\n\r", ch_spo2_valid);
     
141.         }
     
142.         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);
     
143.     }
     
144. }