Arduino interrupt framework.ino

# This code hasn't been compiled or tested. You may encounter errors.

#define ISR_PIN 3
#define OTHER_PIN 8
#defin LED_PIN 13

volatile int last_other_value = 0;
volatile int other_value = 0;

void setup()
{
  Serial.begin(250000);
  pinMode(OTHER_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  attachInterrupt(digitalPinToInterrupt(ISR_PIN), isr, RISING);
}

void loop()
{
  Serial.print(last_other_value);
  Serial.print(" ");
  Serial.print(other_value);        
  Serial.println();
  
  digitalWrite(LED_PIN, other_value != last_other_value);
}

void isr() {
  last_other_value = other_value;
  other_value = digitalRead(OTHER_PIN);
}

ibt_2-bts7960-test.ino

#define ENCODER_A 3
#define ENCODER_B 4
#define PWM_OUTPUT 11
#define SENSOR 0 // potentiometer wiper
#define LED_PIN 9
#define PID_INTERVAL 19
#define ERROR_SIZE 16

#define Kp -1

double control = 0;
double motor_drive_value = 0;

volatile int encoder_position = 0;
int last_encoder_position = 0;

int last_millis = 0;
unsigned long last_pid = 0;

double error = 0;

double current_rpm = 0;

unsigned long ms;

int delta_encoder = 0;

double set_point;

#define INPUT_INSTRUCTION_BYTES 1
#define INPUT_DATA_BYTES 4
#define INPUT_SIZE  INPUT_INSTRUCTION_BYTES + INPUT_DATA_BYTES
char input[INPUT_INSTRUCTION_BYTES + INPUT_DATA_BYTES];

void setup()
{
  Serial.begin(250000);
  pinMode(PWM_OUTPUT, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(8, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(ENCODER_A), encoder_isr, CHANGE);
}

void loop()
{
  ms = millis();
  if (ms - last_pid > PID_INTERVAL) {
    // SET POINT INPUT
    int sensor_value = analogRead(SENSOR);
    set_point = (double)map(sensor_value, 2, 1021, 0, 10000)/100.0;

    // GET SPEED
    int delta_encoder = encoder_position - last_encoder_position;
    int delta_ms = ms - last_millis;
    current_rpm = delta_encoder * 37.5 / delta_ms;

    // PID SHIT
    error = current_rpm - set_point;

    control = constrain(Kp*error, -5, 5);
    motor_drive_value = motor_drive_value + control;

    // OUT
    analogWrite(PWM_OUTPUT, motor_drive_value);
    if (digitalRead(8) == LOW) {
      analogWrite(PWM_OUTPUT, 0);
    }
    
    Serial.print(set_point);
    Serial.print(" ");

    Serial.print(error);
    Serial.print(" ");
    
    Serial.print(current_rpm);   
    Serial.print(" ");

    Serial.print(control);
    Serial.print(" ");
        
    Serial.println();


    // UPDATE LAST
    last_encoder_position = encoder_position;
    last_millis = ms;
    last_pid = ms;
  }
}

void encoder_isr() {
  bool dir = digitalRead(ENCODER_B) != digitalRead(ENCODER_A);
  if (dir) {
    encoder_position ++;
  } else {
    encoder_position --;
  }
  digitalWrite(LED_PIN, dir);
}