Tone generation library

Cool stuff!
Thanks for sharing the code.

nice one thanxxx

Very cool! I will try it.
Thanks!
Julián

awesome work keep it up..........

Does the Tone Library work with an ATmega328P running at 1MHz from the internal oscillator? The tones seem way too low but I could easily be doing something wrong.

Is anyone else interested in the Tone Library working at 1MHz?

Why not modify the play method in that library to multiply the given frequency by 16. You could use the F_CPU define or clockCyclesPerMicrosecond() to check the actual clock frequency assuming you are setting this in your boards.txt file

adding something like this at the top of the play method should work (although I have not tried it):
frequency = frequency * (16 / clockCyclesPerMicrosecond());

Thank you for the reply.

Why not modify the play method in that library to multiply the given frequency by 16

Good thinking! That will at least tell me if I'm doing somthing wrong or if there's a deficiency in the library.

You could use the F_CPU define

The library uses F_CPU to calculate the configuration values for the counter. Unfortunately, I suspect the various frequency / divisor ranges are designed to only work for 16MHz and 8MHz clocks.

assuming you are setting this in your boards.txt file

I am. And from some blink / delay testing I think I did it correctly.

adding something like this at the top of the play method should work (although I have not tried it):
frequency = frequency * (16 / clockCyclesPerMicrosecond());

I think it will work for 16MHz and 1MHz but it will probably not work for 8MHz. But, I'll certainly try it.

The prescalar selection for the timers were based on 16 MHz (and they we're OK for 8 MHz, but not great).

I changed the code to scan for the best prescalar based on the frequency and cpu clock.

I've uploaded a new version - I haven't tested it out on hardware just yet, but it does compile. Please test it and let me know if it works for you.

http://code.google.com/p/arduino-tone/source/browse/trunk/Tone.cpp

b

It works well for higher frequencies but a tone that should be 100Hz is 555Hz on one of the pins.

I tested using this sketch on an a standard 16mhz ATmega168 :

#include <Tone.h>

int notes[] = { 20,50, 100, 1000, 5000, 10000, 15000, 20000};
Tone notePlayer[2];

void setup(void)
{
  Serial.begin(9600);
  notePlayer[0].begin(11);
  notePlayer[1].begin(12);
}

void loop(void)
{
  char c;

  if(Serial.available())
  {
    c = Serial.read();
    
    switch(c)
    {
      case 'a' ... 'h':

        notePlayer[0].play(notes[c - 'a']);
        Serial.print("pin 11:");
        Serial.println(notes[c - 'a']);
        break;
      case 's':
        notePlayer[0].stop();
        break;

      case 'A'...'H':   
        notePlayer[1].play(notes[c - 'A']);
        Serial.print("pin 12:");
        Serial.println(notes[c - 'A']);
        break;
      case 'S':
        notePlayer[1].stop();
        break;

      default:
        notePlayer[1].stop();
        break;
    }
  }
}

Setting both outputs to 100Hz, I measured a period of just over 1.8ms on pin12. The period onr pin 11 was spot on (9.982ms).

The original code was never intended to produce frequencies below 123 Hz, because @16MHz, the 16 bit timers (set at ck/1) could not kill enough time to produce tones lower than that.

Thus, I've rewritten the code to accommodate almost all frequencies now on the 16 bit timers (2 -> 65535 Hz). 8 Bit timers will still choke, but now at 31 Hz.

http://code.google.com/p/arduino-tone/source/browse/#svn/trunk

(note: you'll have to get Tone.h as well now, because of the declaration change).

Coding Badly: Test it at 1MHz - let me know how it goes.

b

Thanks bhagman and mem! I should have time tonight for some testing.


[edit]The results seem to be the same. At 8MHz NOTE_B2 is lower than at 16MHz. At 1MHz NOTE_B2 is even lower. I suspect I need to sleep on it... Good night to all! (or morning or afternoon to those not in America)[/edit]

Hi, i try, this and it seems that i can only have 2 tone?
the third one does not run?
i have a atmega 328 and it should give me 3 tone (at least this is what i anderstand in the .cpp and .h
am i wrong?
Thanks
Patgadget

#include <Tone.h>
Tone tone1;
Tone tone2;
Tone tone3;
void setup()
{
  tone1.begin(13);
  tone2.begin(12);
  tone3.begin(6);
  tone3.play(100);
  tone1.play(35);
  tone2.play(35);
}
void loop()
{
}

Patgadget: Silly boundary conditions. Amazing what a difference >= makes compared to >. Fixed. Get the latest version from Google Code SVN. Thanks for finding it.

Coding Badly: hmmm... methinks you have something else going on. Are you compiling the sketches against F_CPU set to 1MHz? Or are you just compiling based on an Duemilanove w/ATmega32 (@16 MHz) and putting it into a chip running at 1MHz? I'm betting dollars to donuts that you're doing the latter.

b

Coding Badly: hmmm... methinks you have something else going on

That's what I suspect but I cannot figure out what.

Are you compiling the sketches against F_CPU set to 1MHz?

That part seems to be working. I've tried simple delay and beep Sketches (e.g. blink an LED every second then count the blinks in one minute) and they seem to work well. As expected, the uncalibrated internal oscillator is a bit off (~3% fast).

Or are you just compiling based on an Duemilanove w/ATmega32 (@16 MHz) and putting it into a chip running at 1MHz?

This is the entry in boards.txt I'm using...

rdbare328a1MHz.name=Bare / Breadboard ATmega328 @ 1MHz
rdbare328a1MHz.upload.using=pololu
rdbare328a1MHz.upload.maximum_size=32768
rdbare328a1MHz.build.mcu=atmega328p
rdbare328a1MHz.build.f_cpu=1000000L
rdbare328a1MHz.build.core=arduino

I left out the bootloader entries because I'm not using a bootloader.

I'm betting dollars to donuts that you're doing the latter

I'll take that bet! But I do suspect the problem lies with me.

For what it's worth, I built an Excel spreadsheet to calculate the ocr and prescaler values. The frequencies are all within 2% so it doesn't appear to be a problem with the math.

Unfortunately, I don't think I'll have time to work on it for a few days and possibly for a week. I'll report back when I can...

Thanks that fixed the 3 tone problem, now i got another one?
if i write this should not i get a different tone at every 2 seconds??
i even try to add a tone1.stop just after the delay and it still give me always the same tone?
Any clues. (BTW i was running arduino 13)

#include <Tone.h>
Tone tone1;
Tone tone2;
Tone tone3;
void setup()
{
  tone1.begin(13);
  tone2.begin(12);
  tone3.begin(6);
  tone3.play(100);
  tone2.play(35);
}
void loop()
{
tone1.play(random(35,55));
delay(2000);
}

Coding Badly: ok, so how many donuts do you have on you right now? :wink: How far out are the frequencies? Are they close to the RC oscillator error? (i.e. ~3%). Gimme some actual figures and I can help out.

Patgadget: Ah yes... Remember: delay() is broken when you use the third (on the '328) timer to produce tones. (delay() sits in an infinite loop because the timer has been reallocated)

Also, although it's the last timer to be allocated, timer 0 (which is used for millis() among other things) will be affected if used.

you could try this:

void loop()
{
  tone1.play(random(35,55), 2000);
  while (tone1.isPlaying());
}

Note: it won't matter which Tone instance you use. If you've allocated 3 Tones, delay() and anything else that depends on millis() will be broken.

Perfect that fix all my problem.
Patgadget

Sweet. Moving to V0005.

b

I finally figured out what's wrong. Tone.o is not being rebuilt when I switch "boards". Because of various warnings, I know at least some of the other libraries are rebuilt when I switch. I don't have the patience to figure out why the Tone library is orphaned and deleting Tone.o after a switch is an easy work-around so I'm moving on to the next hurdle.

Thank you mem and bhagman for your help!