arduino interrupt variable not working - arduino

Question

I am a beginner with arduino and I'm trying to make a sinus wave generator. Since I've recently found I can't put everything into main void loop, I'm trying to use interrupts. I have problem with changing variable inside of the interrupt (Delay), I don't know where's the mistake.
Here is my code:
int sine256[] = { //256 sin values from 0 to 2pi
};
int i = 0;
int sensorPin = 7;
int outputPin = 6;
volatile float Delay = 10000;
void setup()
{
Serial.begin(9600);
pinMode(outputPin, OUTPUT);
pinMode(sensorPin, INPUT);
attachInterrupt(digitalPinToInterrupt(sensorPin), freq, RISING);
}
void loop()
{
analogWrite(6,sine256[i]);
i = i + 1;
if(i == 256){
i = 0;
}
Serial.println(Delay);
delayMicroseconds(Delay);
}
void freq() {
Delay = Delay/2;
}

Answer 1

EDIT
Try this:
int sine256[] = { //256 sin values from 0 to 2pi
};
int i = 0;
int sensorPin = 7;
int outputPin = 6;
volatile float Delay = 10000;
void setup()
{
Serial.begin(9600);
pinMode(outputPin, OUTPUT);
pinMode(sensorPin, INPUT);
//attachInterrupt(digitalPinToInterrupt(sensorPin), freq, RISING);
}
void loop()
{
analogWrite(6,sine256[i]);
i = i + 1;
if(i == 256){
i = 0;
}
Serial.println(Delay);
freq();
delay(Delay);
}
void freq() {
Delay = Delay / 2;
}
https://www.arduino.cc/en/Reference/AttachInterrupt
Try taking a look at that.
What model are you using?

Answer 2

The only thing that causes me troubles now is the button; when i press it, it often respond as if i had pressed the button multiple times (2,3 or 4x).
This is my final code for now. Since the execution time for a void loop is 12 microseconds, i've calculated delay required to run a generator on 20,40 & 60Hz.
int sine256[] = { //256 sin values from 0 to 2pi (from 0 to 255)
int i = 0;
int sensorPin = 2;
volatile int outputPin = 7;
volatile float Delay = 1000;
int time1;
int time2;
void setup()
{
Serial.begin(9600);
pinMode(outputPin, OUTPUT);
pinMode(sensorPin, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(sensorPin), freq, FALLING);
}
void loop()
{
//time1 = micros();
analogWrite(outputPin,sine256[i]);
i = i + 1;
if(i == 256){
i = 0;
}
//time2 = micros();
//Serial.println(time2 - time1);
delay(Delay);
}
void freq() {
outputPin = 6;
if(Delay == 0.02){
analogWrite(6,LOW);
outputPin = 7;
Delay = 1000;
}
if(Delay == 0.04){
Delay = 0.02;
}
if(Delay == 0.09){
Delay = 0.04;
}
if((Delay == 1000)&&(outputPin == 6)){
Delay = 0.09;
}
Serial.println(Delay);
}