robert@285: /*
robert@285:  ____  _____ _        _    
robert@285: | __ )| ____| |      / \   
robert@285: |  _ \|  _| | |     / _ \  
robert@285: | |_) | |___| |___ / ___ \ 
robert@285: |____/|_____|_____/_/   \_\.io
robert@285: 
robert@285:  */
robert@285: 
robert@285: /**
robert@285: \example 3_scope_analog
robert@285: 
robert@285: Connecting potentiometers
robert@285: -------------------------
robert@285: 
robert@285: This example reads from analogue inputs 0 and 1 via `analogReadFrame()` and 
robert@285: generates a sine wave with amplitude and frequency determined by their values. 
robert@285: It's best to connect a 10K potentiometer to each of these analog inputs. Far 
robert@285: left and far right pins of the pot go to 3.3V and GND, the middle should be 
robert@285: connected to the analog in pins.
robert@285: 
robert@285: The sine wave is then plotted on the oscilloscope. Click the Open Scope button to 
robert@285: view the results. As you turn the potentiometers you will see the amplitude and 
robert@285: frequency of the sine wave change.
robert@285: 
robert@285: This project also shows as example of `map()` which allows you to re-scale a number 
robert@285: from one range to another. Note that `map()` does not constrain your variable 
robert@285: within the upper and lower limits. If you want to do this use the `constrain()`
robert@285: function.
robert@285: 
robert@285: */
robert@285: 
robert@285: 
robert@285: 
robert@285: 
l@273: 
l@273: #include <BeagleRT.h>
l@273: #include <cmath>
l@273: #include <Scope.h>
l@273: 
l@273: Scope scope;
l@273: 
l@273: float gInverseSampleRate;
l@273: float gPhase;
l@273: 
l@273: bool setup(BeagleRTContext *context, void *userData)
l@273: {
l@273: 
l@273:     // setup the scope with 3 channels at the audio sample rate
l@273: 	scope.setup(3, context->audioSampleRate);
l@273: 	
l@273: 	gInverseSampleRate = 1.0 / context->audioSampleRate;
l@273: 	gPhase = 0.0;
l@273: 
l@273: 	return true;
l@273: }
l@273: 
l@273: void render(BeagleRTContext *context, void *userData)
l@273: {
l@273: 
l@273: 	for(unsigned int n = 0; n < context->audioFrames; n++) {
l@273: 	    
l@273: 	    // read analogIn channels 0 and 1
l@273: 	    float in1 = analogReadFrame(context, n, 0);
l@273: 	    float in2 = analogReadFrame(context, n, 1);
l@273: 	    
l@273: 	    // map in1 to amplitude and in2 to frequency
l@273: 	    float amplitude = in1 * 0.8f;
l@273: 	    float frequency = map(in2, 0, 1, 100, 1000);
l@273: 	    
l@273: 	    // generate a sine wave with the amplitude and frequency 
l@273: 	    float out = amplitude * sinf(gPhase);
l@273: 	    gPhase += 2.0 * M_PI * frequency * gInverseSampleRate;
l@273: 		if(gPhase > 2.0 * M_PI)
l@273: 			gPhase -= 2.0 * M_PI;
l@273: 	    
l@273: 	    // log the sine wave and sensor values on the scope
l@273: 	    scope.log(out, in1, in2);
l@273: 	    
l@273: 	    // pass the sine wave to the audio outputs
l@273: 	    for(unsigned int channel = 0; channel < context->audioChannels; channel++)
l@273: 			context->audioOut[n * context->audioChannels + channel] = out;
l@273: 
l@273: 	}
l@273: }
l@273: 
l@273: void cleanup(BeagleRTContext *context, void *userData)
l@273: {
l@273: 
l@273: }