Getting Started with the AutoDriver

This Tutorial is Retired!

This tutorial covers concepts or technologies that are no longer current. It's still here for you to read and enjoy, but may not be as useful as our newest tutorials.

Contributors: SFUptownMaker
Favorited Favorite 1


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.

alt text

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. You'll need to change the example sketch to remove references the boardB, however, and to not use the busy pin.

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 <AutoDriver.h>
#include "notes.h"

// Test sketch for the L6470 AutoDriver library. This program instantiates three
//  AutoDriver boards and uses them 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 instances. The parameters are pin numbers in
//  Arduino-speke for CS and reset.
AutoDriver boardA(10, 6);
AutoDriver boardB(9, 6);

void setup()
  Serial.println("Hello world");

// 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 two AutoDriver boards (as befits our hardware test setup described earlier), call a configuration function, 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);
  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.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. boardB and
                                    //  boardC will be the same in all respects
                                    //  but this, as they will bring in and
                                    //  output the clock to keep them
                                    //  all in phase.
  boardA.setAccKVAL(255);           // We'll tinker with these later, if needed.
  boardA.setHoldKVAL(32);           // This controls the holding current; keep it low.

  boardB.configSyncPin(BUSY_PIN, 0);// BUSY pin low during operations;
                                    //  second paramter ignored.
  boardB.configStepMode(STEP_FS);   // 0 microsteps per step
  boardB.setMaxSpeed(10000);        // 10000 steps/s max
  boardB.setFullSpeed(10000);       // microstep below 10000 steps/s
  boardB.setAcc(10000);             // accelerate at 10000 steps/s/s
  boardB.setSlewRate(SR_530V_us);   // Upping the edge speed increases torque.
  boardB.setOCThreshold(OC_750mA);  // OC threshold 750mA
  boardB.setPWMFreq(PWM_DIV_2, PWM_MUL_2); // 31.25kHz PWM freq
  boardB.setOCShutdown(OC_SD_DISABLE); // don't shutdown on OC
  boardB.setVoltageComp(VS_COMP_DISABLE); // don't compensate for motor V
  boardB.setSwitchMode(SW_USER);    // Switch is not hard stop
  boardB.setOscMode(EXT_16MHZ_OSCOUT_INVERT); // for boardB, we want 16MHz
                                    //  external osc source, 16MHz out.
  boardB.setAccKVAL(255);           // We'll tinker with these later, if needed.
  boardB.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.