annotate examples/11-Extras/7segment/render.cpp @ 464:8fcfbfb32aa0 prerelease

Examples reorder with subdirectories. Added header to each project. Moved Doxygen to bottom of render.cpp.

/*
 ____  _____ _        _    
| __ )| ____| |      / \   
|  _ \|  _| | |     / _ \  
| |_) | |___| |___ / ___ \ 
|____/|_____|_____/_/   \_\

The platform for ultra-low latency audio and sensor processing

http://bela.io

A project of the Augmented Instruments Laboratory within the
Centre for Digital Music at Queen Mary University of London.
http://www.eecs.qmul.ac.uk/~andrewm

(c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
  Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
  Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.

The Bela software is distributed under the GNU Lesser General Public License
(LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
*/


#include <Bela.h>

#define NUM_PINS 12

// Breadboard wiring layout:
// 11 10 12 9  8  7
// [ LED DISP ]
// 1  2  3  6  4  5

// Organised by display segments:
// e d . X c g b X X X f a
const int kPins[NUM_PINS] = {P8_07, P8_08, P8_09, P8_10, P8_11, P8_12,
							 P8_15, P8_16, P8_27, P8_28, P8_29, P8_30};

// Indices into the above array: pins 12, 9, 8, 6
const int kDigits[4] = {9, 8, 7, 3};

int gCurrentlyDisplayingDigit = 0;
int gDigitDisplayTime = 0;
const int kDigitMaxDisplayTime = 44;

int gState = 0;
int gStateCounter = 0;
const int kMaxState = 25;

// . g f e d c b a
//const unsigned char kBELA[4] = {0x7C, 0x79, 0x38, 0x77};
const unsigned char kBELA[4] = {0x7C, 0x7B, 0x38, 0x5F};
const unsigned char kPerimeter[6] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20};

int gCharacterToDisplay[4] = {0, 0, 0, 0};
	
// 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)
{	
	// This project makes the assumption that the audio and digital
	// sample rates are the same. But check it to be sure!
	if(context->audioFrames != context->digitalFrames) {
		rt_printf("Error: this project needs the audio and digital sample rates to be the same.\n");
		return false;
	}
	
	for(int i = 0; i < NUM_PINS; i++) {
		pinMode(context, 0, kPins[i], 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, numMatrixFrames
// will be 0.

void render(BelaContext *context, void *userData)
{
	for(unsigned int n = 0; n < context->audioFrames; n++) {
		// Check for rotation between digits
		if(--gDigitDisplayTime <= 0) {
			gCurrentlyDisplayingDigit = (gCurrentlyDisplayingDigit + 1) % 4;
			gDigitDisplayTime = kDigitMaxDisplayTime;
		}
	
		// Write the currently displaying digit low and the rest high
		for(int i = 0; i < 4; i++)
				digitalWriteOnce(context, n, kPins[kDigits[i]], HIGH);
		digitalWriteOnce(context, n, kPins[kDigits[gCurrentlyDisplayingDigit]], LOW);
		
		// Write the digit to the other outputs
		digitalWriteOnce(context, n, kPins[11],
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x01);	// a
		digitalWriteOnce(context, n, kPins[6], 
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x02);	// b
		digitalWriteOnce(context, n, kPins[4], 
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x04);	// c
		digitalWriteOnce(context, n, kPins[1],
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x08);	// d
		digitalWriteOnce(context, n, kPins[0],
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x10);	// e
		digitalWriteOnce(context, n, kPins[10],
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x20);	// f
		digitalWriteOnce(context, n, kPins[5],
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x40);	// g
		digitalWriteOnce(context, n, kPins[2],
			gCharacterToDisplay[gCurrentlyDisplayingDigit] & 0x80);	// .
			
		// Check for changing state
		if(--gStateCounter <= 0) {
			gState = (gState + 1) % kMaxState;
			if(gState != (kMaxState - 1)) {
				for(int i = 0; i < 4; i++)
					gCharacterToDisplay[i] = 1 << (gState % 6);
				gStateCounter = 2000;
			}
			else {
				for(int i = 0; i < 4; i++)
					gCharacterToDisplay[i] = kBELA[i];
				gStateCounter = 50000;
			}
		}
	}
}

// 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)
{
	
}