robert@269: /*
robert@269:  ____  _____ _        _    
robert@269: | __ )| ____| |      / \   
robert@269: |  _ \|  _| | |     / _ \  
robert@269: | |_) | |___| |___ / ___ \ 
robert@269: |____/|_____|_____/_/   \_\.io
robert@269: 
robert@269:  */
robert@269: 
giuliomoro@246: /*
giuliomoro@77:  *
giuliomoro@77:  * Andrew McPherson and Victor Zappi
giuliomoro@77:  * Queen Mary, University of London
giuliomoro@77:  */
giuliomoro@77: 
robert@269: /**
robert@269: \example 2_digital_button
robert@269: 
robert@269: Switching an LED on and off
robert@269: ---------------------------
robert@269: 
robert@285: This example brings together digital input and digital output. The program will read 
robert@269: a button and turn the LED on and off according to the state of the button.
robert@269: 
robert@269: - connect an LED in series with a 470ohm resistor between P8_07 and ground.
robert@269: - connect a 1k resistor to P9_03 (+3.3V),
robert@269: - connect the other end of the resistor to both a button and P8_08
robert@269: - connect the other end of the button to ground.
robert@269: 
robert@269: You will notice that the LED will normally stay on and will turn off as long as 
robert@269: the button is pressed. This is due to the fact that the LED is set to the same 
robert@269: value read at input P8_08. When the button is not pressed, P8_08 is `HIGH` and so 
robert@269: P8_07 is set to `HIGH` as well, so that the LED conducts and emits light. When 
robert@269: the button is pressed, P8_08 goes `LOW` and P8_07 is set to `LOW`, turning off the LED.
robert@269: 
robert@269: As an exercise try and change the code so that the LED only turns on when 
robert@285: the button is pressed.
robert@269: */
robert@269: 
robert@269: 
giuliomoro@77: #include <BeagleRT.h>
giuliomoro@77: #include <Utilities.h>
giuliomoro@77: #include <cmath>
giuliomoro@77: #include <rtdk.h>
giuliomoro@246: #include <stdlib.h>
giuliomoro@77: 
giuliomoro@77: // setup() is called once before the audio rendering starts.
giuliomoro@77: // Use it to perform any initialisation and allocation which is dependent
giuliomoro@77: // on the period size or sample rate.
giuliomoro@77: //
giuliomoro@77: // userData holds an opaque pointer to a data structure that was passed
giuliomoro@77: // in from the call to initAudio().
giuliomoro@77: //
giuliomoro@77: // Return true on success; returning false halts the program.
giuliomoro@77: 
giuliomoro@77: bool setup(BeagleRTContext *context, void *userData)
giuliomoro@77: {
giuliomoro@246: 	pinModeFrame(context, 0, P8_08, INPUT);
giuliomoro@246: 	pinModeFrame(context, 0, P8_07, OUTPUT);
giuliomoro@77: 	return true;
giuliomoro@77: }
giuliomoro@77: 
giuliomoro@77: // render() is called regularly at the highest priority by the audio engine.
giuliomoro@77: // Input and output are given from the audio hardware and the other
giuliomoro@77: // ADCs and DACs (if available). If only audio is available, numAnalogFrames
giuliomoro@77: // will be 0.
giuliomoro@77: 
giuliomoro@77: /* basic_button
giuliomoro@77: * - connect an LED in series with a 470ohm resistor between P8_07 and ground.
giuliomoro@77: * - connect a 1k resistor to P9_03 (+3.3V), 
giuliomoro@77: * - connect the other end of the resistor to both a button and P8_08
giuliomoro@77: * - connect the other end of the button to ground.
giuliomoro@77: * The program will read the button and make the LED blink when the button is pressed.
giuliomoro@77: */
giuliomoro@77: 
giuliomoro@77: void render(BeagleRTContext *context, void *userData)
giuliomoro@77: {
giuliomoro@77: 	for(unsigned int n=0; n<context->digitalFrames; n++){
giuliomoro@223: 		int status=digitalReadFrame(context, 0, P8_08); //read the value of the button
giuliomoro@246: 		digitalWriteFrameOnce(context, n, P8_07, status); //write the status to the LED
giuliomoro@246: 		float out = 0.1 * status * rand() / (float)RAND_MAX * 2 - 1; //generate some noise, gated by the button
giuliomoro@246: 		for(unsigned int j = 0; j < context->audioChannels; j++){
giuliomoro@246: 			audioWriteFrame(context, n, j, out); //write the audio output
giuliomoro@246: 		}
giuliomoro@223: 	}
giuliomoro@77: }
giuliomoro@77: 
giuliomoro@77: // cleanup() is called once at the end, after the audio has stopped.
giuliomoro@77: // Release any resources that were allocated in setup().
giuliomoro@77: 
giuliomoro@77: void cleanup(BeagleRTContext *context, void *userData)
giuliomoro@77: {
giuliomoro@77: 	// Nothing to do here
giuliomoro@77: }
giuliomoro@246: