Connection Diagram!

Tone Library for MSP430

We all like things that sound..About a month ago, A friend of mine asked me to make her a musical card..which she wanted to gift to a friend who is a guitarist( She herself knows Piano). She wanted to dedicate the song she made to her..So, she gave me the tones and durations of each tone..So that i can code it and play the tune..Since, Its all monotonic ..so it didnt felt like a piano..but the tone was clear.

Connection Diagram!

The one I gave her had a MSP430g2211. Just to test the tune settings earlier, I had played Happy Birthday..By borrowing the notes from a website.

The notes were:

c c d c f e
c c d c g f
c c highc a bflat g
a a bflat f g f

Earlier.. I made it using the traditional delay way. But later, I figured out how to do it using the Hardware PWM. The trick is that every note has a particular frequency.If we set the channel for  half the duration and then reset it for the next half. We get a PWM of 50% Duty cycle at the given frequency..Taddaa..Thats all..instead of generating  a sine wave, we are making a square wave.

The exact tested frequency for the notes are available here !

This is the function i coded:

void tone(int tone,int duration)  //Tone macro and duration in millisecs.Play other frq simply divide it (smclk/notef) to get the counter period and feed it into the function
{   int i;
	for(i=0;i<duration;i++)
	{ CCR0=tone;       //Tone length
	  CCR1=tone/2;     //Half Tone ON and Half tone OFF i.e 50% duty!
	  _delay_cycles(1000);
	}
}

Now another problem ..was that how to stop the Tone..since it(tone generation) is not done using software bit-banging ..I can`t set the Output to Zero just by clearing the bit..but we can definitely make the period zero. This is how i coded the notone function:

void notone(int i)        //To stop the tone can`t use delay_ms as its a hardware PWM not software!
{

	CCR0=0; //make main period zero..it doesnt work when you set CCR1 to zero because it will always set-reset at zero.
	delay_ms(i);
}

Now we need a toneInit() Function..to initialize the PWM:

void toneInit() //Initialise The Timers
{

CCTL1 = OUTMOD_7; // CCR1 reset/set

TACTL = TASSEL_2 + MC_1; // SMCLK, up mode
}

Hope You all like it. If anyone wants the Complete Code..He/She can comment with the email id. The comments are moderated.So don`t worry about your mail ids going public. 🙂
Here`s the video..Wish a geek Happy Birthday!

I know the camera is bad! The tone can be tinkered/tuned a bit..I leave to the reader.. 😛

UPDATE: 30th Nov`12

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Update 6th Dec:

You can fork the code from github here.

DRC-TI-BoosterPack

MSP430 Based Touch Interaction

I recently ‘got’ a Capacitive Booster Pack from Ti in a competition.

I decided to play some games involving simple controls with it.It is a great little booster pack which lets you do cool stuff like gesture recognition ( Touch gestures..like rotate,slide etc.). As an initial experiment i decided to play Poto and Cabenga  . It is a funny little time killing game..where all you need to do it to just press the “SPACE-BAR” ..Cool enough..for lazy geeks(ahemm like me)..

I decided to do it using the

TI MSP430 Launchpad + Capacitive Booster Pack+ Some Windows Shell Scripting

This is what i got:

Just wave the hand above it to get it out of the LPM(Low Power Mode)..this activates the script and then until it sleeps..the script is active..

Hope you like it..I will post the scripts soon..So stay tuned!