quick and dirty L298N motor control for arduino

control.ino

#define MOTOR1_CW   3
#define MOTOR1_CCW  5
#define MOTOR2_CW   6
#define MOTOR2_CCW  9

#define STATE_MOTOR     0
#define STATE_DIRECTION 1
#define STATE_SPEED     2

#define BUFFER_SIZE 10

typedef unsigned char u8_t;

u8_t buffer[BUFFER_SIZE];
u8_t buffer_pos = 0;

u8_t motor;
u8_t direction;
u8_t speed;

u8_t state = STATE_MOTOR;


void setup() {
  pinMode(MOTOR1_CW,  OUTPUT);
  pinMode(MOTOR1_CCW, OUTPUT);
  pinMode(MOTOR2_CW,  OUTPUT);
  pinMode(MOTOR2_CCW, OUTPUT);
       
  
  Serial.begin(9600);
}

void loop() {
  u8_t input;
  
  while(Serial.available() < 1);
  Serial.println(F("Process"));

  input = Serial.read();

  if(',' == input || '\n' == input) {
    Serial.println(F("found delimiter"));
    switch(state)
    {
      case STATE_MOTOR:
      Serial.println(F("case motor"));
      motor = atoi(buffer);
      Serial.print(F("Motor="));
      Serial.println(motor);
      memset(buffer, 0, BUFFER_SIZE);
      buffer_pos = 0;
      state = STATE_DIRECTION;
      return;

      case STATE_DIRECTION:
      Serial.println(F("case direction"));
      direction = atoi(buffer);
      Serial.print(F("Direction="));
      Serial.println(direction);
      memset(buffer, 0, BUFFER_SIZE);
      buffer_pos = 0;
      state = STATE_SPEED;
      return;

      case STATE_SPEED:
      Serial.println(F("case speed"));
      speed = atoi(buffer);
      Serial.print(F("Speed="));
      Serial.println(speed);
      memset(buffer, 0, BUFFER_SIZE);
      buffer_pos = 0;
      state = STATE_MOTOR;
      //update
      Serial.println(F("update pins"));
      if(motor == 1 && direction == 1) {analogWrite(MOTOR1_CW, speed); analogWrite(MOTOR1_CCW, 0);}
      if(motor == 1 && direction == 2) {analogWrite(MOTOR1_CCW, speed); analogWrite(MOTOR1_CW, 0);}
      if(motor == 2 && direction == 1) {analogWrite(MOTOR2_CW, speed); analogWrite(MOTOR2_CCW, 0);}
      if(motor == 2 && direction == 2) {analogWrite(MOTOR2_CCW, speed); analogWrite(MOTOR2_CW, 0);}
      return;
    }
  }
  else
  {
    Serial.print(F("append to buffer:"));
    Serial.println(input);
    buffer[buffer_pos++] = input;
  }
  
}