Hola qué tal.
El proyecto que estoy realizando es reproducir voz humana con el PWM encontrado en el Playground de ejemplos de arduino, con la diferencia de que debe recibir los datos de una comunicación serial.
El problema principal aqui es que si el Arduino recibe los datos de una conexión USB, el sonido se escucha entendible, pero si lo hace desde un XBEE, se escucha puro ruido y no se logra entender ni una sola palabra del sonido a reproducir.
Por favor, ayúdenme, ya he estado intentando en esto como más de dos meses, y no encuentro solución. Mil gracias
El proyecto que estoy realizando es reproducir voz humana con el PWM encontrado en el Playground de ejemplos de arduino, con la diferencia de que debe recibir los datos de una comunicación serial.
El problema principal aqui es que si el Arduino recibe los datos de una conexión USB, el sonido se escucha entendible, pero si lo hace desde un XBEE, se escucha puro ruido y no se logra entender ni una sola palabra del sonido a reproducir.
Por favor, ayúdenme, ya he estado intentando en esto como más de dos meses, y no encuentro solución. Mil gracias
Código:
int a = 0;
int ledPin = 13;
int speakerPin = 11;
char inData[3];
char numero[3]; // Allocate some space for the string
char inChar; // Where to store the character read
byte index = 0; // Index into array; where to store the character
long arraySize = 999999;
byte num;
/*
* speaker_pcm
*
* Plays 8-bit PCM audio on pin 11 using pulse-width modulation (PWM).
* For Arduino with Atmega168 at 16 MHz.
*
* Uses two timers. The first changes the sample value 8000 times a second.
* The second holds pin 11 high for 0-255 ticks out of a 256-tick cycle,
* depending on sample value. The second timer repeats 62500 times per second
* (16000000 / 256), much faster than the playback rate (8000 Hz), so
* it almost sounds halfway decent, just really quiet on a PC speaker.
*
* Takes over Timer 1 (16-bit) for the 8000 Hz timer. This breaks PWM
* (analogWrite()) for Arduino pins 9 and 10. Takes Timer 2 (8-bit)
* for the pulse width modulation, breaking PWM for pins 11 & 3.
*
* References:
* http://www.uchobby.com/index.php/2007/11/11/arduino-sound-part-1/
* http://www.atmel.com/dyn/resources/prod_documents/doc2542.pdf
* http://www.evilmadscientist.com/article.php/avrdac
* http://gonium.net/md/2006/12/27/i-will-think-before-i-code/
* http://fly.cc.fer.hr/GDM/articles/sndmus/speaker2.html
* http://www.gamedev.net/reference/articles/article442.asp
*
* Michael Smith <michael@hurts.ca>
*/
#include <stdint.h>
#include <avr/interrupt.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#define SAMPLE_RATE 8000 //8KHz sample rate
/*
* The audio data needs to be unsigned, 8-bit, 8000 Hz, and small enough
* to fit in flash. 10000-13000 samples is about the limit.
*
* sounddata.h should look like this:
* const int sounddata_length=10000;
* const unsigned char sounddata_data[] PROGMEM = { ..... };
*
* You can use wav2c from GBA CSS:
* http://thieumsweb.free.fr/english/gbacss.html
* Then add "PROGMEM" in the right place. I hacked it up to dump the samples
* as unsigned rather than signed, but it shouldn't matter.
*
* http://musicthing.blogspot.com/2005/05/tiny-music-makers-pt-4-mac-startup.html
* mplayer -ao pcm macstartup.mp3
* sox audiodump.wav -v 1.32 -c 1 -r 8000 -u -1 macstartup-8000.wav
* sox macstartup-8000.wav macstartup-cut.wav trim 0 10000s
* wav2c macstartup-cut.wav sounddata.h sounddata
*/
//#include "sounddata.h"
#define SAMPLEINDEX_MASK 0x0FFF
//Used to implement phase increment resampling
uint16_t sampleStep; //The step size for each sample. All 16 bits are used.
//The lower 12 are fractional steps. A step size of 0x01000 is equal to one step
//per sample. Also, this means that playback can be done at a maximum of 16X the
//orignal rate.
volatile unsigned long sampleIndex; //Keeps the current sample index.
//Used by the ISR and initalizaiton methods
uint16_t samplePoint;
unsigned int sampleValue;
//Prototype for DAC output function
//The idea is to abstract the type of DAC used. It is assumed that the DAC would never have more then
//16 bits of resolution so an unsigned int is used. If you intened to have 8-Bits of resolution then you
//need to upshift the input (value<<8). This does add some time/hassel but it support the concept of
//differnet resolutions independent of the applicaiton code.
//The second parameter is the DAC channel. For the inital test code one is used for the PWM DAC and
//and the other is for the R2R DAC. In a future version I want to have Left and Right channels
//
#define DAC_PWM 1
#define DAC_R2R 2
void SetDAC(unsigned int outputValue, unsigned int channel);
//Lower level funcitons to actualy set the specific DAC type. Used only by the SetDAC funciton.
void SetDAC_PWM(unsigned int outputValue);
void SetDAC_R2R(unsigned int outputValue);
ISR(TIMER1_COMPA_vect) {
}
void startPlayback() {
pinMode(speakerPin, OUTPUT);
sampleStep=0x2000; //Set to orignal sample rate.
// Set up Timer 2 to do pulse width modulation on the speaker
// pin.
// Use internal clock (datasheet p.160)
ASSR &= ~(_BV(EXCLK) | _BV(AS2));
// Set fast PWM mode (p.157)
TCCR2A |= _BV(WGM21) | _BV(WGM20);
TCCR2B &= ~_BV(WGM22);
// Do non-inverting PWM on pin OC2A (p.155)
// On the Arduino this is pin 11.
TCCR2A = (TCCR2A | _BV(COM2A1)) & ~_BV(COM2A0);
TCCR2A &= ~(_BV(COM2B1) | _BV(COM2B0));
// No prescaler (p.158)
TCCR2B = (TCCR2B & ~(_BV(CS12) | _BV(CS11))) | _BV(CS10);
// Set initial pulse width to the first sample.
//sampleValue=pgm_read_byte(&sounddata_data[0])<<8;
//sampleValue = num;
// SetPWMDAC(sampleValue);
// SetR2RDAC(sampleValue);
// Set up Timer 1 to send a sample every interrupt.
// cli();
// Set CTC mode (Clear Timer on Compare Match) (p.133)
// Have to set OCR1A *after*, otherwise it gets reset to 0!
TCCR1B = (TCCR1B & ~_BV(WGM13)) | _BV(WGM12);
TCCR1A = TCCR1A & ~(_BV(WGM11) | _BV(WGM10));
// No prescaler (p.134)
TCCR1B = (TCCR1B & ~(_BV(CS12) | _BV(CS11))) | _BV(CS10);
// Set the compare register (OCR1A).
// OCR1A is a 16-bit register, so we have to do this with
// interrupts disabled to be safe.
OCR1A = F_CPU / SAMPLE_RATE; // 16e6 / 8000 = 2000
// Enable interrupt when TCNT1 == OCR1A (p.136)
TIMSK1 |= _BV(OCIE1A);
// lastSample = pgm_read_byte(&sounddata_data[sounddata_length-1]);
//sampleIndex = 0;
// sei();
}
void SetDAC(unsigned int outputValue, unsigned int channel) {
switch(channel) {
case DAC_PWM :
SetDAC_PWM(outputValue);
break;
case DAC_R2R :
SetDAC_R2R(outputValue);
break;
}
}
//Set the PWM D/A converter output
void SetDAC_PWM(unsigned int outputValue){
//This implementation uses PWM in 8 bit mode.
//Load the upper 8 bits into the PWM control register
OCR2A = (outputValue>>8)&0xFF;
}
//Set the R2R D/A converter output.
void SetDAC_R2R(unsigned int outputValue){
//We are using port D bits 2-7 for a 6-bit D/A.
//Bits 0 and 1 are serial which we dont want to disturb
PORTD=(PIND&0x03)|((outputValue>>8)&0xFC);
}
#define MAX_STEP 0x05000
#define MIN_STEP 0x00400
void setup() {
//Set the LED pin mode to output.
pinMode(ledPin, OUTPUT);
//Iniciar el serial a 115200 bps
Serial.begin(142500);
//2 bits de paro / 2 stop bits
// UCSR0C = UCSR0C | B00001000;
// UCSR0C |= (1 << USBS0); // right after calling Serial.begin ();
pinMode(speakerPin, OUTPUT);
//Setup the hardware for the D/A converter
//We are using port D bits 2-7 for a 6-bit D/A.
//Bits 0 and 1 are serial which we dont want to disturb
// DDRD|=B11111110; //Set upper 6 as ouput, lower are TX and RX
//Set an inital phase step size.
sampleStep=MIN_STEP;
//Setup the timers for the ISR and PCM generation
startPlayback();
//Parpadear LED para indicar que funciona correctamente
for (int i = 0; i<3; i++){
digitalWrite(ledPin,HIGH);
delay(250);
digitalWrite(ledPin,LOW);
delay(250);
}
}
void loop() {
//To demonstrate the phase steping feature set the phase step as a function
//of the A/D input on input 0. Hook up a pot to vary the phase step and resample the
//sound at diffenret frequencies.
//for(int i = 0; i<255;i++)
//sampleStep=MIN_STEP+(analogRead(0)<<3);
//sampleStep=MIN_STEP+i;
while(Serial.available() > 0) // Don't read unless you know there is data
{
digitalWrite(ledPin,HIGH);
if(index < arraySize) // One less than the size of the array
{
inChar = Serial.read(); // Read a character
//Que reciba caracteres hasta que llegue una coma
if (inChar!=','){
inData[index] = inChar; // Store it
index++; // Increment where to write next
inData[index] = '\0'; // Null terminate the string
}
//Si el caracter es coma, que lo mande a numero
if(inChar==','){
for(int i = 0; i<3;i++){
numero[i]='\0';//Borrar cada caracter de numero para poder escribir en el de nuevo
if(inData[i]!='\0')
numero[i] = inData[i];
}
//Ahora en entero
char * thisChar = numero;
a = atoi(thisChar);
num = a;
index = 0;
}
}
//delay(10);
OCR2A = num;//QUe lo saque por el pwm
//SetDAC(a, DAC_PWM);
digitalWrite(ledPin,LOW);
}
}
