Adafruit PIR Sensor - troubleshooting code

So I'm trying to send a serial string when the sensor detects motion and then every ten seconds thereafter. I can't find what's wrong with my code, but the sensor works with other sketches and the serial connection works. Any ideas? Much obliged.

const int pirPin = A0;
long lastmotion;
long now;
int LED = 13;
bool pirON = false;


void setup()
{
  pinMode(pirPin, INPUT);
  Serial.begin(9600);
}
 
void loop()
{
  now = millis(); // assign counter to current time...ish
  if (digitalRead(pirPin) == HIGH){  // if motion detected
    digitalWrite(LED, HIGH);
    if (pirON = false){    //if previous motion didn't happen
      Serial.println("item=motionevent;");
      pirON = true;      // establish that a previous event happened
      lastmotion = now;  // establish time of last event
    }
  }
  
  
  if (pirON = true){    //if event happened
    if (now > (lastmotion+10000l)){   // and it was more than ten seconds ago
      pirON = false;                 // reset previous motion event
      digitalWrite(LED, LOW);
    }
  }
}

can't find what's wrong with my code

You haven't said what it's doing that's wrong....

Classic C pitfall. This:

  if (pirON = true){    //if event happened

should be:

  if (pirON == true){    //if event happened

That's probably it - thank you! Will test now...