Getting Started with the AutoDriver - v13

Contributors: SFUptownMaker
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Single Board Example

Having covered the hardware setup and the use of the library, all that remains is to provide an example sketch for the AutoDriver board.

This sketch allows you to play music by controlling the step rate of your motor. The default song it plays is the first part of "Want You Gone" by Jonathon Coulton. I'm only including the main file and the support functions here; the notes.h and wantYouGone() function files are available on the board's GitHub page.

Connecting one Autodriver board

If you skipped over the Test Hardware Assembly page, and just want to hook up an AutoDriver to an Arduino or RedBoard as easily as possible, see the above diagram.

Because of the size and complexity of this sketch, it has been broken into several files. Please be sure you have all the files downloaded!

Setup() and Loop()

#include <SparkFunAutoDriver.h>
#include <SPI.h>
#include "SparkFunnotes.h"

// Test sketch for the L6470 AutoDriver library. This program instantiates one
//  AutoDriver board and uses it to play Jonathon Coulton's "Want You Gone" from
//  the Portal 2 soundtrack. In a more general sense, it adds support for playing
//  music with stepper motors. Not all notes can be played, of course- at too high
//  a steps/sec rate, the motors will slip and dogs and cats will live together.

// Create our AutoDriver instance. The parameters are the position in the chain of
//  boards (with board 0 being located at the end of the chain, farthest from the
//  controlling processor), CS pin, and reset pin.
AutoDriver boardA(0, 10, 7);

void setup()
  Serial.println("Hello world");  
  // Start by setting up the SPI port and pins. The
  //  Autodriver library does not do this for you!
  pinMode(7, OUTPUT);
  pinMode(MOSI, OUTPUT);
  pinMode(MISO, INPUT);
  pinMode(13, OUTPUT);
  pinMode(10, OUTPUT);
  digitalWrite(10, HIGH);
  digitalWrite(7, LOW);       // This low/high is a reset of the L6470 chip on the
  digitalWrite(7, HIGH);      //  Autodriver board, and is a good thing to do at
                              //  the start of any Autodriver sketch, to be sure
                              //  you're starting the Autodriver from a known state.

// loop() waits for a character- any character- and then plays the song.
void loop()
  if (Serial.available() !=0)
    Serial.println("Play it!");
    Serial.println("Done playing!");

In the main file, you can see that there's not much going on. We initiate one AutoDriver board (as befits our hardware test setup described earlier), call a configuration function, initialize our SPI port and pins, then wait around for a user to request us to play the music.

Support Functions

// Support functions.

#define NOTE_DIVISOR 2  // My cheesy way of reducing the note frequencies to a range
                        //  that doesn't cause the motor to slip. I *could* rewrite
                        //  the wantYouGone() function to change the notes, but that
                        //  would be a lot of work.

int stepDir = 1;        // Direction flipping bit. Rather than all going one way,
                        //  they change directions. It looks cooler.

// To play a note, we start the motor spinning at the note's frequency in steps/s.
//  The run() function automagically calculates the appropriate value to feed to the
//  dSPIN part based on the desired steps/s.
void playNote(int note, int duration)
  if (stepDir == 1), note/NOTE_DIVISOR);
  else     , note/NOTE_DIVISOR);
  while (boardA.busyCheck());

// This is the configuration function for the two dSPIN parts. Read the inline
//  comments for more info.
void dSPINConfig(void)
  boardA.SPIPortConnect(&SPI);      // Before doing anything else, we need to
                                    //  tell the object which SPI port to use.
                                    //  Some devices may have more than one.

  boardA.configSyncPin(BUSY_PIN, 0);// BUSY pin low during operations;
                                    //  second paramter ignored.
  boardA.configStepMode(STEP_FS);   // 0 microsteps per step
  boardA.setMaxSpeed(10000);        // 10000 steps/s max
  boardA.setFullSpeed(10000);       // microstep below 10000 steps/s
  boardA.setAcc(10000);             // accelerate at 10000 steps/s/s
  boardA.setSlewRate(SR_530V_us);   // Upping the edge speed increases torque.
  boardA.setOCThreshold(OC_750mA);  // OC threshold 750mA
  boardA.setPWMFreq(PWM_DIV_2, PWM_MUL_2); // 31.25kHz PWM freq
  boardA.setOCShutdown(OC_SD_DISABLE); // don't shutdown on OC
  boardA.setVoltageComp(VS_COMP_DISABLE); // don't compensate for motor V
  boardA.setSwitchMode(SW_USER);    // Switch is not hard stop
  boardA.setOscMode(INT_16MHZ_OSCOUT_16MHZ); // for boardA, we want 16MHz
                                    //  internal osc, 16MHz out.
  boardA.setAccKVAL(128);           // We'll tinker with these later, if needed.
  boardA.setHoldKVAL(32);           // This controls the holding current; keep it low.

The supportFunctions file has a good example of the settings used to configure the AutoDriver boards for this application, as well as a nice example of using the run() and softStop() functions to control the motion of the motor.