Blink Without Delay Problem on Arduino

Well, not for all, but for me it becomes problem while turning led on using analogWrite command, some led just won’t completely shut down.

(Maybe it completely unrelated, but my analog reading on A0 is oscillating, very unstable)



I have the commands packed on a function

unsigned long t0 = 0;
const long dt = 1000;       
void blinkNoD(int pin) {
  unsigned long t = millis();
  if(t - t0 >= dt) {
    t0 = t;
    led=!led;   
    digitalWrite(pin, led);
  }
} 

Since I already have delay in loop, and it really messed with the timing (not mention that maybe the analog reading instability have anything to do with it), I decided to modify the blink code, still without delay command.

unsigned long t0 = 0;
const long dt = 1;       
void blinkNoD(int pin) {
  t0 += dt
  if(t0 >= 4) {
    t0 = 0;
    led=!led;   
    digitalWrite(pin, led);
  }
} 

It turned out that my analogRead instability is another problem, get to work on it, :)