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extern "C" void __cxa_pure_virtual(void); //for C++ defines
/*
Electric data access template
TJR 191011
Uses Arduino c++ libraries in vanilla AVR environment
Explanation
http://www.johnhenryshammer.com/WOW2/pagesHowTo/atmelPage.php#index
*/
#define SAMPLES 512 //size of ram buffer
#define PACKETSIZE 320 //size of output packet
#include <WProgram.h> //import main Arduino header file
byte dd[SAMPLES]; // ram buffer
int loopCount=0;
int sample=0;
void fill_sinewave(){
/*
sample data to stream
the vital thing is that its possible to distinguish the end of a packet
here the data is in the range 1-255 and a 0 denotes the end of the packet
*/
float pi = 3.141592;
float fcnt=0;
float fd;
float dx=2 * pi / SAMPLES; // fill the 512 byte bufferarry
int bb;
for (int i = 0; i <SAMPLES ; i++){ // with 50 periods sinewawe
fd= 127*sin(fcnt); // fundamental tone
fcnt=fcnt+dx; // in the range of 0 to 2xpi and 1/512 increments
bb=128+fd; // add dc offset to sinewawe
dd[i]=bb; // write value into array
}
}
int main(){
//init(); -- init Arduino library - delay, PWM setup messes with timers, millis(), micros() etc don't work without it
fill_sinewave();
Serial.begin(115200);
DDRB |= (1 << 5); // port B bit 6 = arduino pin 13
PORTB = (1 << 5); //turn on to start
TCCR1B |= (1 << WGM12); // Configure timer 1 for CTC mode
TIMSK1 |= (1 << OCIE1A); // Enable CTC interrupt
OCR1A = 390; // Set CTC compare value: final speed = CPU clocks / prescaler / CTC 15625=1Hz
sei(); // Enable global interrupts
while(1) {
if (Serial.available() > 0) {
PORTB ^= (1 << 5);
byte in=Serial.read();
if (in=='a') {
Serial.println("Welcome to electic");
TCCR1B |= ((1<<CS10)|(1 << CS12)); // Set up timer at Fcpu/1024
}
}
}
}
ISR(TIMER1_COMPA_vect)
{
//if (enabled)
PORTB ^= (1 << 5);
for (int i=0;i<PACKETSIZE;i++) {
Serial.write(dd[sample]);
sample=(sample+1)%SAMPLES;
}
Serial.write((byte)0);
}
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