How to connect DRV-8835 to arduino

Question

I try to connect arduino with motor using DRV-8835. The problem I have - simply nothing happens. I used tutorial from http://www.instructables.com/id/The-SnapMobile-Start-Your-Physical-Computing-Engin/step6/Building-the-Prototype-Wiring-Up-the-Arduino-the-D/

Code for arduino:

void setup() {
    pinMode(7, OUTPUT);
    pinMode(5, OUTPUT);
    pinMode(8, OUTPUT);
}

void loop() {
  digitalWrite(8, HIGH);
  digitalWrite(7, HIGH);
  analogWrite(5, 255);
}

Maybe someone has scheme how to connect wires to motor. Now I'm not sure if I made a mistake or motor driver is broken.

Answer 1

Try this code:

void setup() {
    pinMode(8, OUTPUT);//MODE
    pinMode(5, OUTPUT);//AENBL
    pinMode(7, OUTPUT);//APHASE
}

void loop() {
  pinMode(7, HIGH);//APHASE
  pinMode(8, HIGH);//MODE
  pinMode(5, HIGH);//AENBL
  delay(200);
  pinMode(5, LOW);//AENBL
}

Here is a description of the breakout board, this shows a requirement of PWM on AENBL for speed control. Try different delays.

Answer 2

Setting AENBL HIGH should drive the motor at full speed - it has the same effect as analogWrite(5, 255). Dropping it from high to low should stop the motor.

Are you sure the DRV8835 is working properly? You can in theory diagnose it with a logic analyzer, but a scope will work better as the motor outputs aren't really logic. My test setup (yeah, I had one die on me) watched PHASE (just make sure it would toggle), MODE (should be HIGH), and AENBL (should show a square wave for the PWM duty cycle) as logic inputs, then watched the motor outputs on the scope to verify that one of them is the inverse of AENBL and the other is HIGH. Which follows AENBL and which is HIGH depends on PHASE, so you can toggle it if you can only check one output.