The PWM DC motor control is implemented by manipulating two digital IO pins and two PWM pins.

As illustrated in the diagram above (Figure 5), Pin 4,7 (7,8 for old Romeo version) are motor

direction control pins, Pin 5,6 (6,9 for old Romeo version) are motor speed control pins.

For previous Romeo board, the pins used to control the motor is Pin 7,8 (Direction), Pin 6,9 (Speed).

You can find the information at the right side of the Motor Control Pin Jumpers.

Sample Code：

//Standard PWM DC control

int E1 = 5;

//M1 Speed Control

int E2 = 6;

//M2 Speed Control

int M1 = 4;

//M1 Direction Control

int M2 = 7;

//M1 Direction Control

///For previous Romeo, please use these pins.

//int E1 = 6;

//M1 Speed Control

//int E2 = 9;

//M2 Speed Control

//int M1 = 7;

//M1 Direction Control

//int M2 = 8;

//M1 Direction Control

void stop(void)

//Stop

{

digitalWrite(E1,LOW);

digitalWrite(E2,LOW);

}

void advance(char a,char b)

//Move forward

{

analogWrite (E1,a);

//PWM Speed Control

digitalWrite(M1,HIGH);

analogWrite (E2,b);

digitalWrite(M2,HIGH);

}

void back_off (char a,char b)

//Move backward