LeafLabs Garden

A place to share, learn, and grow...

1. 

   kenji
   Member

   Hi,

   when implement tone() Schedule?

   Thanks

   Posted 4 years ago #
2. 

   gbulmer
   Moderator

   kenji - you could try to use the timer setPeriod function described at
   http://leaflabs.com/docs/lang/api/hardwaretimer.html#lang-hardwaretimer
   with setCount.

   there are multiple timers, so you could have independent tones (one frequency per timer) on different pins.

   Posted 4 years ago #
3. 

   manitou
   Member

   Here's a snippet of code for tone() that I used to test some of the arduino sketches on the RET6. A more general version would check that pin provided is PWM and then lookup the corresponding timer/channel

   // for maple pwm pins associated with specific timer/channel
   // pin 24   timer 4 channel 4
   #define TonePin 24
   #define DUTY 2    //2 50%   4 25% hi
   
   HardwareTimer timer(4);
   
   // freq in Hz    duration in ms
   void tone(int pin, int freq, int duration) {
       timer.pause();
       pinMode(pin,PWM);
           timer.setPrescaleFactor(72);  // microseconds
           timer.setOverflow(1000000/freq);
       timer.setMode(TIMER_CH4,TIMER_PWM);
       timer.setCompare(TIMER_CH4,1000000/freq/DUTY);
           timer.setCount(0);      // probaby doesn't matter
       timer.refresh(); // start it up
           timer.resume();
       delay(duration);
   
       timer.pause();
   }

   Posted 3 years ago #
4. 

   poslathian
   LeafLabs

   manitou, nice!

   hardware tone() is the way to go.

   Posted 3 years ago #
5. 

   feurig
   Member

   Thats a lot nicer than arduino/wirings tone which arbitrarily steals timer resources in the background. I think examples like this which are small enough though still requiring a little work to understand are vastly better than everything hidden.

   ++good.

   Posted 3 years ago #
6. 

   gbulmer
   Moderator

   feurig - strongly agree with you.
   A few 'Goldilocks' examples (not too big, not too small, not too hard, not too easy :-) that do interesting things motivate learning.

   good += HUGE_GOODNESS

   Posted 3 years ago #
7. 

   compuslave
   Member

   The only speaker I have is one of those 0-30V piezos from radio shack. I get the same tone, same duration no matter what I do with the variables. Hints?

   The sketch
   [quote]
   // for maple pwm pins associated with specific timer/channel
   // pin 24 timer 4 channel 4
   #define TonePin 9
   #define DUTY 2 //2 50% 4 25% hi

   HardwareTimer timer(4);

   void setup() {
   }

   // freq in Hz duration in ms
   void tone(int pin, int freq, int duration) {
   timer.pause();
   pinMode(pin,PWM);
   timer.setPrescaleFactor(72); // microseconds
   timer.setOverflow(1000000/freq);
   timer.setMode(TIMER_CH4,TIMER_PWM);
   timer.setCompare(TIMER_CH4,1000000/freq/DUTY);
   timer.setCount(0); // probaby doesn't matter
   timer.refresh(); // start it up
   timer.resume();
   delay(duration);

   timer.pause();
   }

   void loop(){

   tone(9, 2000, 200);
   delay(500);
   }
   [/quote]

   Posted 3 years ago #
8. 

   mikep
   Member

   Do you have a link to the RadioShack part? Most piezo's have the tone generator built in, they run off DC, and have a constant frequency. So you won't hear any change in tone with those. Also, piezos have usually a limited frequency range. You need a real speaker like this: http://www.radioshack.com/product/index.jsp?productId=2062406
   But don't hook it up the to the Maple directly, 8 Ohm resistance is too much current to handle for the maple, you need a transistor in between to amplify the Maple output current.

   Posted 3 years ago #
9. 

   compuslave
   Member

   I suspected that may be the case and it appears so. http://www.radioshack.com/product/index.jsp?productId=2062397

   Thanks for your help

   Posted 3 years ago #
10. 

    compuslave
    Member

    Well I tried a speaker, same thing. One tone no matter what I change. Changing pins changes the tone a little, but nothing huge. I have changed everything I can think of to make it sound different, and nothing. Duration variable seems useless as well. The pin variable is the only one that makes any change.

    Thanks for your help, though.

    Posted 3 years ago #
11. 

    gbulmer
    Moderator

    Have you tested the pin+speaker to prove it works?

    For example:

    void loop() {
        pinMode(TonePin,OUTPUT);
        for (int i=100; i<1000; i+= 50) {
            for (int j=0; j<500; j++) {
                  digitalWrite(TonePin, HIGH);
                  delayMicroseconds(i);
                  digitalWrite(TonePin, LOW);
                  delayMicroseconds(i);
             }
        }
    }

    Does that make a falling tone?

    (WARNING: That code is not tested, or even compiled)

    Posted 3 years ago #
12. 

    manitou
    Member

    You chose to define TonePin as 9. That won't work. it has to be pin 24 so that the timer channel matches up with the pin. You can choose another pin, but you'll need to look up the associated timer and channel and modify Tone() accordingly.

    Posted 3 years ago #
13. 

    compuslave
    Member

    Thanks for the code snippet, gbulmer. It would not build, though. I have been pretty busy/preoccupied lately as my wife and I's home burnt. We live in a motorhome, so it doesn't take much of a fire to set you back lol. Once we get our new living quarters, I'll be back on it, though. Thanks again!

    manitou, great info, thanks! I'll try this as well. I'm not sure why I have become so side tracked by a homegrown tone() function, but I have. I bet one thing for sure, when it's all done and tone() works, I'll know more about this board than when I started and I'll know things I doubt I would have learned doing any other project.

    Anyway, thanks guys! I didn't just leave, just been busy with thangs.

    Posted 3 years ago #
14. 

    manitou
    Member

    Note that the pin/timer/channel mappings differ based on the version of Maple you are using. My example was for an RET6. Check the pin mappings for your Maple model. (As noted, a more robust version of tone() could use the pin number to look up the timer/channel ....)

    Posted 3 years ago #
15. 

    manitou
    Member

    Here is v2 of a snippet of code for tone that follows the Arduino implementation more closely. It uses a timer/interrupt and any digital pin. It also uses the funky duration logic of Arduino.
    

    volatile static int toggle_count=0;
    static int tone_pin;
    
    HardwareTimer timer(2);
    
    // freq in Hz    duration in ms
    void tone(int pin, int frequency, int duration) {
    	timer.pause();
    	pinMode(pin,OUTPUT);
    	tone_pin = pin;
    	if (duration > 0 ) toggle_count = 2 * frequency * duration / 1000;
    	 else toggle_count = -1;
    //	timer.setPeriod(2*1000000/freq);   // in microseconds
            timer.setPrescaleFactor(CYCLES_PER_MICROSECOND);  // microseconds
            timer.setOverflow(1000000/frequency/2);
    	timer.setChannel1Mode(TIMER_OUTPUT_COMPARE);
    	timer.setCompare(TIMER_CH1, 1);  // Interrupt 1 count after each update
    	timer.attachCompare1Interrupt(handler_tone);
    	timer.refresh(); // start it up
            timer.resume();
    }
    
    void noTone(int pin) {
        timer.pause();
        digitalWrite(pin,LOW);
    }
    
    // ISR
    void handler_tone(void) {
    	if (toggle_count != 0){
        	togglePin(tone_pin);
    	if (toggle_count > 0)  toggle_count--;
    	} else noTone(tone_pin);
    }

    Posted 3 years ago #

RSS feed for this topic

Reply

You must log in to post.