Colony » Colony Scout

/*

 * ARM -> us

 * -height setpoint

 *

 * us -> ARM

 * -tracking ID (same for all forklifts)

 * -serial number (unique to each forklift)

 * -current height

 * -current height setpoint

 * -payload weight

 *

 */

#include "twi.h"

#include "analog.h"

#include "motor.h"

#include <avr/io.h>

#include <avr/interrupt.h>

#define TRACKING_ID 0x41

#define SERIAL_NUMBER 0x12

// indicies for forklift internal data

#define FORKLIFT_TRACKING_ID       0

#define FORKLIFT_SERIAL_NUMBER     1

#define FORKLIFT_HEIGHT            2

#define FORKLIFT_HEIGHT_SETPOINT   3 // r/w

#define FORKLIFT_LINE_POS          4

#define FORKLIFT_LINE_THRESH_HIGH  5 // r/w

#define FORKLIFT_LINE_THRESH_LOW   6 // r/w

#define FORKLIFT_LINE_VALS_START   7

#define FORKLIFT_LINE_VALS_END    12 // non-inclusive

#define FORKLIFT_DATA_LEN         12

uint8_t internal_index = 0;

uint8_t internal_data[] = {

  TRACKING_ID,

  SERIAL_NUMBER,

  0,

  100, // default height setpoint

  0,

  0,

  150, // default line threshold

  0,

  0,

  0,

  0,

  0

};

int error;

int i_term;

void init_int0(void)

{

  TCCR0B = (1<<CS02)|(1<<CS00); //Timer clock = system clock / 1024

  TIFR0 = 1<<TOV0; //Clear TOV0  clear pending interrupts

  TIMSK0 = 1<<TOIE0; //Enable Timer0 Overflow Interrupt

}

void slave_rx(uint8_t* data, int len)

{

  if (len > 0 && data[0] < FORKLIFT_DATA_LEN)

  {

    internal_index = data[0];

    if (len > 1)

    {

      if (internal_index == FORKLIFT_HEIGHT_SETPOINT)

      {

          internal_data[internal_index] = data[1];

          i_term = 0;

      }

      else if (internal_index == FORKLIFT_LINE_THRESH_HIGH)

      {

        internal_data[internal_index] = data[1];

        line_set_threshold_high(data[1]);

      }

      else if (internal_index == FORKLIFT_LINE_THRESH_LOW)

      {

        internal_data[internal_index] = data[1];

        line_set_threshold_low(data[1]);

      }

    }

  }

}

void slave_tx(void)

{

  twi_transmit(&internal_data[internal_index], 1);

  internal_index++;

  if (internal_index >= FORKLIFT_DATA_LEN)

    internal_index = 0;

}

int clamp(int min, int max, int val)

{

  if (val > max) return max;

  if (val < min) return min;

  return val;

}

SIGNAL(TIMER0_OVF_vect)

{

  // TODO make this more easily tunable (despite integer limitations)

  int height = (int)internal_data[FORKLIFT_HEIGHT];

  error = (int)internal_data[FORKLIFT_HEIGHT_SETPOINT] - height;

  i_term = i_term + error/4;

  int speed = clamp(-127, 127, i_term/12 + error*4);

  if (height < 15 && speed < 0) speed = 0;

  if (height > 240 && speed > 0) speed = 0;

  set_motor(speed);

}

int main()

{

  int i;

  error = 0;

  i_term = 0;

  init_int0();

  sei();

  twi_attachSlaveRxEvent(slave_rx);

  twi_attachSlaveTxEvent(slave_tx);

  twi_setAddress(TRACKING_ID);

  twi_init();

  analog_init();

  motor_init();

  while (1)

  {

    for (i = 0; i < 5; i++)

      internal_data[i + FORKLIFT_LINE_VALS_START] = line_read(i) >> 2;

    internal_data[FORKLIFT_LINE_POS] = line_read_pos();

    internal_data[FORKLIFT_HEIGHT] = 255 - (analog_read(ADC_HEIGHT) >> 2);

  }

  return 0;

}