Mercurial > hg > beaglert
view examples/basic_blink/render.cpp @ 372:db2fe4e1b88e prerelease
Doxygen content added to each example render.cpp.
References to AnalogReadFrame etc. removed from doxygen content.
author | Robert Jack <robert.h.jack@gmail.com> |
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date | Thu, 09 Jun 2016 18:16:05 +0100 |
parents | 02c4ca0e3718 |
children | 9dc5a0ccad25 |
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/* ____ _____ _ _ | __ )| ____| | / \ | _ \| _| | | / _ \ | |_) | |___| |___ / ___ \ |____/|_____|_____/_/ \_\.io */ /* * * Andrew McPherson and Victor Zappi * Queen Mary, University of London */ /** \example 2_digital_blink Blinking an LED --------------- This sketch shows the simplest case of digital out. - Connect an LED in series with a 470ohm resistor between P8_07 and ground. The led is blinked on and off by setting the digital pin `HIGH` and `LOW` every interval seconds which is set in `render()`. In `setup()` the pin mode must be set to output mode via `pinMode()`. For example: `pinMode(context, 0, P8_07, OUTPUT)`. In `render()` the output of the digital pins is set by `digitalWrite()`. For example: `digitalWrite(context, n, P8_07, status)` where `status` can be equal to either `HIGH` or `LOW`. When set `HIGH` the pin will give 3.3V, when set to `LOW` 0V. To keep track of elapsed time we have a sample counter count. When the count reaches a certain limit it switches state to either `HIGH` or `LOW` depending on its current value. In this case the limit is `context->digitalSampleRate*interval` which allows us to write the desired interval in seconds, stored in `interval`. */ #include <Bela.h> #include <Utilities.h> #include <cmath> #include <rtdk.h> // setup() is called once before the audio rendering starts. // Use it to perform any initialisation and allocation which is dependent // on the period size or sample rate. // // userData holds an opaque pointer to a data structure that was passed // in from the call to initAudio(). // // Return true on success; returning false halts the program. bool setup(BelaContext *context, void *userData) { pinMode(context, 0, P8_07, OUTPUT); return true; } // render() is called regularly at the highest priority by the audio engine. // Input and output are given from the audio hardware and the other // ADCs and DACs (if available). If only audio is available, numAnalogFrames // will be 0. /* basic_blink * Connect an LED in series with a 470ohm resistor between P8_07 and ground. * The LED will blink every @interval seconds. */ void render(BelaContext *context, void *userData) { static int count=0; //counts elapsed samples float interval=0.5; //how often to toggle the LED (in seconds) static int status=GPIO_LOW; for(unsigned int n=0; n<context->digitalFrames; n++){ if(count==context->digitalSampleRate*interval){ //if enough samples have elapsed count=0; //reset the counter // status=digitalRead(context, 0, P8_07); if(status==GPIO_LOW) { //toggle the status digitalWrite(context, n, P8_07, status); //write the status to the LED status=GPIO_HIGH; } else { digitalWrite(context, n, P8_07, status); //write the status to the LED status=GPIO_LOW; } } count++; } } // cleanup() is called once at the end, after the audio has stopped. // Release any resources that were allocated in setup(). void cleanup(BelaContext *context, void *userData) { // Nothing to do here }