robert@269: /*
robert@269:  ____  _____ _        _    
robert@269: | __ )| ____| |      / \   
robert@269: |  _ \|  _| | |     / _ \  
robert@269: | |_) | |___| |___ / ___ \ 
robert@269: |____/|_____|_____/_/   \_\.io
robert@269: 
robert@269:  */
robert@269: 
robert@269: /*
robert@269:  *
robert@269:  * Andrew McPherson and Victor Zappi
robert@269:  * Queen Mary, University of London
robert@269:  */
robert@269: 
robert@269: /**
robert@269: \example 2_digital_blink
robert@269: 
robert@269: Blinking an LED
robert@269: ---------------
robert@269: 
robert@269: This sketch shows the simplest case of digital out. Connect an LED in series with
robert@269: a 470ohm resistor between P8_07 and ground. The led is blinked on and off by 
robert@269: setting the digital pin `HIGH` and `LOW` every interval seconds (set it in the 
robert@269: `render()` function).
robert@269: 
robert@269: Firstly the pin mode must be set to output mode: 
robert@269: `pinModeFrame(context, 0, P8_07, OUTPUT);` in the `setup()` function. The output 
robert@269: of the digital pins is set by the following code: 
robert@269: `digitalWriteFrame(context, n, P8_07, status);` where status can be equal to 
robert@269: either `HIGH` or `LOW`. When set `HIGH` the pin will give 3.3V, when set to 
robert@269: `LOW` 0V.
robert@269: 
robert@269: To keep track of elapsed time we have a sample counter count. When count reaches 
robert@269: a certain limit it switches state to either `HIGH` or `LOW` depending on its current 
robert@269: value. In this case the limit is `context->digitalSampleRate*interval` which 
robert@269: allows us to write the desired interval in seconds, stored in `interval`.
robert@269: */
robert@269: 
robert@269: 
robert@269: 
robert@269: 
robert@269: 
giuliomoro@74: #include <BeagleRT.h>
giuliomoro@74: #include <Utilities.h>
giuliomoro@74: #include <cmath>
giuliomoro@74: #include <rtdk.h>
giuliomoro@74: 
giuliomoro@74: // setup() is called once before the audio rendering starts.
giuliomoro@74: // Use it to perform any initialisation and allocation which is dependent
giuliomoro@74: // on the period size or sample rate.
giuliomoro@74: //
giuliomoro@74: // userData holds an opaque pointer to a data structure that was passed
giuliomoro@74: // in from the call to initAudio().
giuliomoro@74: //
giuliomoro@74: // Return true on success; returning false halts the program.
giuliomoro@74: 
giuliomoro@74: bool setup(BeagleRTContext *context, void *userData)
giuliomoro@74: {
andrewm@81:     pinModeFrame(context, 0, P8_07, OUTPUT);
giuliomoro@74: 	return true;
giuliomoro@74: }
giuliomoro@74: 
giuliomoro@74: // render() is called regularly at the highest priority by the audio engine.
giuliomoro@74: // Input and output are given from the audio hardware and the other
giuliomoro@74: // ADCs and DACs (if available). If only audio is available, numAnalogFrames
giuliomoro@74: // will be 0.
giuliomoro@74: 
giuliomoro@75: /* basic_blink
giuliomoro@75: * Connect an LED in series with a 470ohm resistor between P8_07 and ground.
giuliomoro@75: * The LED will blink every @interval seconds.
giuliomoro@75: */
giuliomoro@75: 
giuliomoro@74: void render(BeagleRTContext *context, void *userData)
giuliomoro@74: {
giuliomoro@74:   static int count=0; //counts elapsed samples
giuliomoro@74:   float interval=0.5; //how often to toggle the LED (in seconds)
giuliomoro@74:   static int status=GPIO_LOW;
giuliomoro@74: 	for(unsigned int n=0; n<context->digitalFrames; n++){
giuliomoro@74:     if(count==context->digitalSampleRate*interval){ //if enough samples have elapsed
giuliomoro@74:       count=0; //reset the counter
giuliomoro@74:     // status=digitalReadFrame(context, 0, P8_07);
andrewm@81:       if(status==GPIO_LOW) { //toggle the status
andrewm@81:           digitalWriteFrame(context, n, P8_07, status); //write the status to the LED
andrewm@81:           status=GPIO_HIGH;
andrewm@81:       }
andrewm@81:       else {
andrewm@81:           digitalWriteFrame(context, n, P8_07, status); //write the status to the LED
andrewm@81:           status=GPIO_LOW;
andrewm@81:       }
giuliomoro@74:     }
giuliomoro@74:     count++;
giuliomoro@74:   }
giuliomoro@74: }
giuliomoro@74: 
giuliomoro@74: // cleanup() is called once at the end, after the audio has stopped.
giuliomoro@74: // Release any resources that were allocated in setup().
giuliomoro@74: 
giuliomoro@74: void cleanup(BeagleRTContext *context, void *userData)
giuliomoro@74: {
giuliomoro@74: 	// Nothing to do here
giuliomoro@74: }