robert@464: /*
robert@464:  ____  _____ _        _    
robert@464: | __ )| ____| |      / \   
robert@464: |  _ \|  _| | |     / _ \  
robert@464: | |_) | |___| |___ / ___ \ 
robert@464: |____/|_____|_____/_/   \_\
robert@464: 
robert@464: The platform for ultra-low latency audio and sensor processing
robert@464: 
robert@464: http://bela.io
robert@464: 
robert@464: A project of the Augmented Instruments Laboratory within the
robert@464: Centre for Digital Music at Queen Mary University of London.
robert@464: http://www.eecs.qmul.ac.uk/~andrewm
robert@464: 
robert@464: (c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
robert@464:   Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
robert@464:   Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.
robert@464: 
robert@464: The Bela software is distributed under the GNU Lesser General Public License
robert@464: (LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
robert@464: */
robert@464: 
robert@464: 
robert@464: #include <Bela.h>
robert@464: #include <cmath>
robert@464: #include <rtdk.h>
robert@464: 
robert@464: bool setup(BelaContext *context, void *userData)
robert@464: {
robert@464:     pinMode(context, 0, P8_07, OUTPUT);
robert@464: 	return true;
robert@464: }
robert@464: 
robert@464: void render(BelaContext *context, void *userData)
robert@464: {
robert@464:   static int count=0; //counts elapsed samples
robert@464:   float interval=0.5; //how often to toggle the LED (in seconds)
robert@464:   static int status=GPIO_LOW;
robert@464: 	for(unsigned int n=0; n<context->digitalFrames; n++){
robert@464:     if(count==context->digitalSampleRate*interval){ //if enough samples have elapsed
robert@464:       count=0; //reset the counter
robert@464:     // status=digitalRead(context, 0, P8_07);
robert@464:       if(status==GPIO_LOW) { //toggle the status
robert@464:           digitalWrite(context, n, P8_07, status); //write the status to the LED
robert@464:           status=GPIO_HIGH;
robert@464:       }
robert@464:       else {
robert@464:           digitalWrite(context, n, P8_07, status); //write the status to the LED
robert@464:           status=GPIO_LOW;
robert@464:       }
robert@464:     }
robert@464:     count++;
robert@464:   }
robert@464: }
robert@464: 
robert@464: void cleanup(BelaContext *context, void *userData)
robert@464: {
robert@464: 	// Nothing to do here
robert@464: }
robert@464: 
robert@464: 
robert@464: /**
robert@500: \example digital-output/render.cpp
robert@464: 
robert@464: Blinking an LED
robert@464: ---------------
robert@464: 
robert@464: This sketch shows the simplest case of digital out. 
robert@464: 
robert@464: - Connect an LED in series with a 470ohm resistor between P8_07 and ground. 
robert@464: 
robert@464: The led is blinked on and off by setting the digital pin `HIGH` and `LOW` every interval seconds which is set in 
robert@464: `render()`.
robert@464: 
robert@464: In `setup()` the pin mode must be set to output mode via `pinMode()`. For example: 
robert@464: `pinMode(context, 0, P8_07, OUTPUT)`. 
robert@464: In `render()` the output of the digital pins is set by `digitalWrite()`. For example: 
robert@464: `digitalWrite(context, n, P8_07, status)` where `status` can be equal to 
robert@464: either `HIGH` or `LOW`. When set `HIGH` the pin will give 3.3V, when set to 
robert@464: `LOW` 0V.
robert@464: 
chris@543: Note that there are two ways of specifying the digital pin: using the GPIO label (e.g. `P8_07`), or using the digital IO index (e.g. 0)
chris@543: 
robert@464: To keep track of elapsed time we have a sample counter count. When the count reaches 
robert@464: a certain limit it switches state to either `HIGH` or `LOW` depending on its current 
robert@464: value. In this case the limit is `context->digitalSampleRate*interval` which 
robert@464: allows us to write the desired interval in seconds, stored in `interval`.
robert@464: */
robert@464: