basestation.c

AVR单片机C语言程序设计实例精粹

/*****************************************************************************
 * basestation.c
 * April 2007
 ****************************************************************************/


/****************************************************************************/
#include <mega644.h>
#include <at86rf230.h>
#include <stdio.h>

#define SAMPLE_TIMEOUT 15

unsigned char sample_timer;

unsigned char led;
unsigned int led_toggle_count;

unsigned char start_time_count;
unsigned int timer_count;
unsigned int cal_burned;
unsigned char r_buffer[6];	//input string
unsigned char old_meters;
unsigned int speed_timer;
unsigned char speed;
float cal_const;
/****************************************************************************
*   This interrupt runs when a compare-match occurs every 1 ms.  It decrements
*   the sample_timer global variable which is then used to determine when the
*   "sample" task runs.
****************************************************************************/
interrupt [TIM0_COMPA] void ms_timer(void)  {
  if (sample_timer > 0) sample_timer--;

  timer_count++;

  PORTD.2 = ~PORTD.2;
}

/****************************************************************************
*   This task runs every 15 ms and requests data from the transmitter each 
*   time sample runs.  It receives the distance, steps, and speed information
*   from the wearable sensor and calculates the calories burned.  
*   and z accelerations going above and below certian thresholds.  The distance, 
*   steps, and speed information is sent to the basestation every time sample runs.  
****************************************************************************/
void sample(void) {
  unsigned char delay;
  // Turn the radio from receive to transmit mode
  RF_rx_to_tx();
  tx_frame_length = 1;
  transmit_frame[0] = DATA_REQ;
  // Get data ready for tx
  RF_download_frame();
  // Transmit  
  RF_transmit_frame();
  RF_wait_for_transmit(); 
  // Turn the radio from transmit to receive mode
  RF_tx_to_rx();                           //get ready to rx
  RF_clear_IRQ();
  delay_us(100);
  delay = RF_receiver_listen_timeout(40);  //listen for 10ms  
  if (delay != 0)  {                       //we have received something
    PORTD.7 = ~PORTD.7;
    RF_upload_frame();


    // Calculations are based on the speed at which the user moves
    // and can change dynamically so set the mult factor
    if (receive_frame[2] < 3)
      cal_const = .00098;
    else if (receive_frame[2] < 5)
      cal_const = .0015;
    else if (receive_frame[2] < 7)
      cal_const = .00192;
    else
      cal_const = .00348;    
    
   // calories burned = factor * weight * time     
    cal_burned = (int)(cal_const * (float)r_buffer[0] * (float)receive_frame[0] / (float)receive_frame[2]);
    if (cal_burned == -1) cal_burned = 0;

    printf("meters: %d steps: %d speed: %d cals burned: %d           \r",
    receive_frame[0], receive_frame[1], receive_frame[2], cal_burned);

    if (old_meters != receive_frame[0])
    { 
      // speed = distance / time * 2.237
      speed = (int)(((1 / timer_count)) * 2237);
      old_meters = receive_frame[0];
      timer_count = 0;
    }

  }

  speed_timer++;

  // LED Toggling code to indicate Mega64 not hung    
/*
  led_toggle_count++;
  if (led_toggle_count == 8)
  {
    led_toggle_count = 0;
    if (led == 0)
    {
      led = 1;
      PORTD.2 = 0;
    }             
    else
    {
      led = 0;
      PORTD.2 = 1;
    }
  }
*/
}

/****************************************************************************
*   This function correctly initializes the necessary control registers and 
*   I/O ports as well as initializes global variables to zero.  Lastly, it
*   enables all interrupts.
*****************************************************************************/
void initialize(void) {
  DDRD.2 = 1;
  PORTD.2 = 1;

  DDRD.7 = 1;
  DDRA = 0xFF;
  PORTA = 0;
  // Initialize Mega64's SPI settings
  init_spi();
  // Initialize transceiver SPI
  RF_init_spi();
  set_transceiver_clock();
  // Put transceiver in receiver mode
  RF_init_receiver();
  PORTD.7 = 0;
  sample_timer = SAMPLE_TIMEOUT;
  TCCR0A = 0b00000010;  //OC0A & OC0B disconnected, WGM set up for CTC mode
  TCCR0B = 0b00000011;  //Timer set up to osc/64... count to 125 for 1 ms
  OCR0A = 125;
  // Interrupt on compare match A
  TIMSK0 = 0b00000010;

  led = 0;
  led_toggle_count = 0;

  start_time_count = 0;
  timer_count = 0;
  cal_burned = 0;
  old_meters = 0;
  speed_timer = 0;

  // Set up UART & print welcome message
  UCSR0B = 0x18 ;
  UBRR0L = 51 ;
  printf("\rWelcome to the Wireless pedometer!            \n\n\n\r") ;

  //Enable interrupts
  #asm
    sei
  #endasm

}


/****************************************************************************
*   This function prints the welcome message to the screen via a serial 
*   connection.  It also prompts the user for their weight which will be used
*   in the calories burned calculation.
*****************************************************************************/
void get_inputs(void) {
  printf("1) Please keep the wearable sensor off\n\r2) Please enter your weight: ");
  scanf("%d",r_buffer);
  printf("%d\n\r3) Please turn on sensor and wait for green light\n\n\n\r", r_buffer[0]);
}


/****************************************************************************
*   The main function starts by calling the initialization function and
*   getting the user's weight.  It then runs whenever the interrupt has counted 
*   down the sample_timer variable to zero.
****************************************************************************/
void main(void)  {
  initialize();
  get_inputs();

  while(1)  {
    if (sample_timer == 0)  {
      sample_timer = SAMPLE_TIMEOUT;
      sample();
    }
  }

}

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