a ver asi
int leds;
int estadoled = LOW;
unsigned long tinicial = 0;
unsigned long intervalo = 1000;
void setup() {
for(leds=8; leds<=12; leds++){
pinMode(leds, OUTPUT);
}
}
void loop() {
tinicial = millis();
for (leds=8; leds <=12; leds++){
if (millis() - tinicial >= intervalo){
digitalWrite (leds, !digitalRead(leds));
tinicial = millis();
}
}
}