quick experiment with chipKit DP32 timers

quick experiment with chipKit DP32 timers

#include <sys/attribs.h>
#define WAVE_SAMPLES 256
uint16_t a;
uint16_t b;
uint16_t d;
uint16_t inc;
boolean c;

boolean togg;
uint16_t sineData [WAVE_SAMPLES];
//
void setup()
{
  Serial.begin(19200);
  initTmr();
  pinMode(A2, INPUT); //
  pinMode(13, OUTPUT); //LED
  sine ();  
}

void loop()
{
  uint16_t aIn =analogRead(A2);
  inc=aIn>>2;
  d=sineData[a];
  //  if(c !=togg){
  //    Serial.println(a);
  //    Serial.println(d);
  //    Serial.println("inc");
  //    Serial.println(inc);
  //    
  //    //Serial.println("togg");
  //    //Serial.println(togg,DEC);
  //  } //
  c=togg;
}

// call interrupt handling vector
extern "C" {

  void __ISR(16, ipl6) int1Handler(void) 
  {
    togg= !togg;
    analogWrite(13, d); //a++;
    //
    //
    a++;
    a+=inc;
    if(a>=WAVE_SAMPLES)
      a-=WAVE_SAMPLES;

    IFS0CLR = 0x80000;// Clear the T4 interrupt flag Bit 19
    //
  }
}

void initTmr(){
  // 
  T4CON=0x0; //Stop timer and clear registers
  T4CONSET = 0x0070; // set prescalar 1:256
  TMR4 = 0x0; //Clear Timer 4 register
  PR4 = 0x1D1; // set timer to 465 
  IFS0CLR = 0x80000;// Clear the T4 interrupt flag Bit 19
  IPC4SET = 0x00000016;// Interrupt priority 5, 2
  IEC0SET = 0x80000;// Enable T4 interrupt Bit 19
  T4CONSET = 0x8000;// Enable Timer4  
}
void sine (){
  uint16_t i;
  for(i=0;i<WAVE_SAMPLES;i++){
    b = 127*sin((2*PI/WAVE_SAMPLES)*i);
    b+=127;
    sineData [i]=b;
  }
}