File content as of revision 5:f9837617817b:

//Micromouse code
#include "mbed.h"
#include "AVEncoder.h"

// set things
Serial pc(SERIAL_TX, SERIAL_RX);
Ticker Systicker;
Timer timer;

PwmOut motor1_forward(PB_10);
PwmOut motor1_reverse(PA_6);
PwmOut motor2_forward(PA_7);
PwmOut motor2_reverse(PB_6);

// TODO: change our encoder pins from AnalogIn into:
// otherwise, we can also use the AVEncoder thing as well.  
AVEncoder l_enco(PA_15, PB_3);
AVEncoder r_enco(PA_1, PA_10);

// gyro
AnalogIn _gyro(PA_0);
// AnalogIn gyro_cal(PC_1) ?? currently this isn't connected. 

//Left Front IR
DigitalOut eLF(PC_3);
AnalogIn rLF(PC_0);
                                                    //PC_4 is an ADC
//Left Side IR
DigitalOut eLS(PC_2);
AnalogIn rLS(PC_1);

//Right Front IR
DigitalOut eRF(PC_12);
AnalogIn rRF(PA_4);

//Right Side IR
DigitalOut eRS(PC_15);
AnalogIn rRS(PB_0);

DigitalOut myled(LED1);

// global variables. 
volatile float gyro_offset = 0;

volatile float line_speed = 1; // currently is in terms of encoder pulses / ms. 
volatile float angl_speed = 0; // should not turn while moving forward.

volatile float line_prevError = 0;
volatile int   enco_prevError = 0;
volatile float gyro_prevError = 0;

volatile float line_accumulator = 0;
volatile float line_decayFactor = 1.5;
volatile float enco_accumulator = 0;
volatile float enco_decayFactor = 1.5;
volatile float gyro_accumulator = 0;
volatile float gyro_decayFactor = 1.5;

volatile float left_speed = 0;
volatile float right_speed = 0;

volatile unsigned long l_pulses = 0;
volatile unsigned long r_pulses = 0;

// pid constants. these need to be tuned. but i set them as a default val for now.
// line refers to the translational speed. 
// enco and gyro will be used primarily for angular speed. 
// (we can change the names later, 
// i added line in after i realized that i already had the angular code)
const float line_propo = 1;
const float line_integ = 0;
const float line_deriv = 0;

const float gyro_propo = 1;
const float gyro_integ = 0;
const float gyro_deriv = 0;

const float enco_propo = 1;
const float enco_integ = 0;
const float enco_deriv = 0;

const float spin_enco_weight = 0.5;
const float spin_gyro_weight = 1 - spin_enco_weight;

// this is just so that we can maintain what state our mouse is in. 
// currently this has no real use, but it may in the future. 
// or we could just remove this entirely. 
typedef enum 
{
    STOPPED, 
    FORWARD, 
    TURNING, 
    UNKNOWN
} STATE;
STATE mouse_state;

// helper functions
void reset();
void offsetCalc();
void stop();
void moveForward();
void turn();

// interrupt stuff. 
void incLENC()
{
    l_pulses++;
}

void incRENC()
{
    r_pulses++;
}

// PID Control
// this contains the simplistic PID control for the most part. 
// we do have to calibrate constants though. 
void systick()
{
    pc.printf("systick ran\r\n");
    if ( mouse_state == STOPPED || mouse_state == UNKNOWN )
    {
        // do nothing? 
        // reset?
        reset();
        offsetCalc();
        return;
    }
    pc.printf("systick ran while state is FORWARD \r\n");
    
    int dt = timer.read_us(); // should be around 1 ms.
    timer.reset();
    
    float line_error = line_speed * dt - 0.5 * ( l_enco.getPulses() - r_enco.getPulses());
    int enco_error = l_enco.getPulses() - r_enco.getPulses();
    float gyro_error = _gyro.read() - gyro_offset;
    
    line_accumulator += line_error;
    enco_accumulator += enco_error;
    gyro_accumulator += gyro_error;
    
    float line_pid = 0;
    line_pid += line_propo * line_error;
    line_pid += line_integ * line_accumulator;
    line_pid += line_deriv * (line_error - line_prevError)/dt;
    
    float enco_pid = 0;
    enco_pid += enco_propo * enco_error;
    enco_pid += enco_integ * enco_accumulator;
    enco_pid += enco_deriv * (enco_error - enco_prevError)/dt;
    
    float gyro_pid = 0;
    gyro_pid += gyro_propo * gyro_error;
    gyro_pid += gyro_integ * gyro_accumulator;
    gyro_pid += gyro_deriv * (gyro_error - gyro_prevError)/dt;
        
    // forward moving pid control. 
    if ( mouse_state == FORWARD )
    {
        float x_error = line_pid;
        float w_error = spin_enco_weight * enco_pid + spin_gyro_weight * gyro_pid;
        left_speed += x_error + w_error;
        right_speed += x_error - w_error;
        
        pc.printf("left_speed: %f, right_speed: %f\r\n", left_speed, right_speed);
        
        moveForward();
        // offsetCalc();
    }
    if ( mouse_state == TURNING )
    {
        // nothing for now. if we turn in place, we assume no pid control.
        // this may have to change when we try curve turns.
    }
    
    line_prevError = line_error;
    enco_prevError = enco_error;
    gyro_prevError = gyro_error;
    
    line_accumulator /= line_decayFactor;
    enco_accumulator /= enco_decayFactor;
    gyro_accumulator /= gyro_decayFactor;
    
    reset();
}

// setup stuff. 
void setup()
{
    pc.printf("Hello World\r\n");
    mouse_state = STOPPED;
    
    eRS = 0;
    eRF = 0;
    eLS = 0;
    eLF = 0;
    
    myled = 1;
    
    // repeat this for some time frame. 
    for ( int i = 0; i < 200; i++ )
        offsetCalc();
    Systicker.attach_us(&systick, 1000);
}

void reset()
{
    l_enco.reset();
    r_enco.reset();
}


// computes gyro_offset
// uses a "weighted" average. 
// idea is that the current gyro offset is weighted more than previous ones. 
    // uses the following y(n) = 1/2 * y(n-1) + 1/2 * x(n). 
    // (therefore y(n) = sum of x(i)/2^i from i from 0 to n.)
    // this maintains that there will be some influence from previous factors, but keeps the current value at a higher weight.
// currently this is only in the setup function. we can run this when the mouse is running in a line
// when we figure out good line running pid.
void offsetCalc()
{
    gyro_offset = gyro_offset / 2 + _gyro.read() / 2;
}


    
int main()
{
    setup();
    mouse_state = FORWARD;
    
    wait(1.5);
    stop();
    
    pc.printf("DONE\r\n");
    
    //while(1)
//    {
//        pc.printf("The left motor is going at speed: %d\r\n", left_speed);  
//        pc.printf("The left motor is going at speed: %d\r\n", right_speed);
//        wait(1);
//    }
}


// movement functions.
void moveForward()
{
    mouse_state = FORWARD;
    
    if ( left_speed > 0 ) // which should be always.
    {
        motor1_forward = left_speed;
        motor1_reverse = 0;
    }
    else
    {
        motor1_forward = 0;
        motor1_reverse = -left_speed;
    }
    
    if ( right_speed > 0 ) // which again should be always.
    {
        motor2_forward = right_speed;
        motor2_reverse = 0;
    }
    else
    {
        motor2_forward = 0;
        motor2_reverse = -right_speed;
    }
}

void stop()
{
    mouse_state = STOPPED;
    
    
    motor1_forward = 1.0;
    motor1_reverse = 1.0;
    motor2_forward = 1.0;
    motor2_reverse = 1.0;
    
    
}

void turn()// maybe split this into two functions?
{
    mouse_state = TURNING; 
    float angle = 0;
    while (angle < 0.9)
    {
        float gyro_val = _gyro.read() - gyro_offset;
        angle += gyro_val;
        
        pc.printf("%f\r\n", angle);
        
        motor1_forward = 0.5;
        motor1_reverse = 0;
        motor2_forward = 0;
        motor2_reverse = 0.5;
    }    
}