const int led1 = 27;
const int led2 = 26;
void setup() {
Serial.begin(115200);
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
}
void loop() {
digitalWrite(led1, HIGH);
digitalWrite(led2, LOW);
delay(1000);
digitalWrite(led1, LOW);
digitalWrite(led2, HIGH);
delay(1000);
}