+#define TWI_ACK TWCR = (1<<TWEA) | (1<<TWINT) | (1<<TWEN) | (1<<TWIE)
+#define TWI_RESET TWCR &= ~((1 << TWSTO) | (1 << TWEN)); TWI_ACK
+#define TWI_NAK TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE)
+#define ENABLE_PWM_MOTOR1 TCCR1A |= (1 << COM1A1)
+#define ENABLE_PWM_MOTOR2 TCCR1A |= (1 << COM1B1)
+#define ENABLE_PWM_MOTOR3 TCCR2 |= (1 << COM21);
+#define ENABLE_PWM_MOTOR4 TCCR0 |= (1 << COM01);
+#define DISABLE_PWM_MOTOR1 TCCR1A &= ~(1 << COM1A1)
+#define DISABLE_PWM_MOTOR2 TCCR1A &= ~(1 << COM1B1)
+#define DISABLE_PWM_MOTOR3 TCCR2 &= ~(1 << COM21);
+#define DISABLE_PWM_MOTOR4 TCCR0 &= ~(1 << COM01);
+
+