- * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included
- * in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
- * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
- * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
- * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
- * OTHER DEALINGS IN THE SOFTWARE.
- *
- * Except as contained in this notice, the name of Maxim Integrated
- * Products, Inc. shall not be used except as stated in the Maxim Integrated
- * Products, Inc. Branding Policy.
- *
- * The mere transfer of this software does not imply any licenses
- * of trade secrets, proprietary technology, copyrights, patents,
- * trademarks, maskwork rights, or any other form of intellectual
- * property whatsoever. Maxim Integrated Products, Inc. retains all
- * ownership rights.
- *******************************************************************************
- */
- /*!\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 conversion\n\r");
- // 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<n_ir_buffer_length;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_max<aun_red_buffer[i])
- un_max=aun_red_buffer[i]; //update signal max
- pc.printf("red=");
- pc.printf("%i", aun_red_buffer[i]);
- pc.printf(", ir=");
- pc.printf("%i\n\r", 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_max<aun_red_buffer[i])
- un_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=%i\n\r", 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);
- }
- }
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