Output voltage of KA03 motor shield

Arduino(TM) Shields KA03/VMA03
1

Hello,

    I have attached a KA03 motor shield to an Arduino Uno. I have set the voltage input to EXT and supplied 12 VDC. I am using pin 6 for PWM channel A and pin 7 for DIR channel A and disabled channel B by removing the jumpers. I modified the  sample code supplied with the motor shield.


int pwm_a = 6;  //PWM control for motor output 1
int dir_a = 7;  //direction control for motor output 1

void setup()
{
  Serial.begin(9600);     // initialize serial communication:
  pinMode(pwm_a, OUTPUT);  //Set control pins to be outputs
  pinMode(dir_a, OUTPUT);
}

void loop()
{
  digitalWrite(dir_a, LOW);
  analogWrite(pwm_a, 255); // +1.3 VDC
  delay(5000);

  analogWrite(pwm_a, 0);  //  0 VDC
  delay(5000);

  digitalWrite(dir_a, HIGH);
  analogWrite(pwm_a, 255);  //  -1.3 VDC
  delay(5000);

  analogWrite(pwm_a, 0);   //  0 VDC
  delay(5000);
}

My output voltage is 1.3 VDC and - 1.3 VDC. I am expecting 12 VDC. Please advise! Thank you!!