After execute the program of below, the 13 pin output is 4.8v. Why it's not 3.3v?

void setup() {
  // put your setup code here, to run once:
  pinMode(13, OUTPUT);

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(13, HIGH);

The Atheros chip on the Yún is run off 3.3V, but the AVR chip, which is what is connected to the external pins, runs off 5V. What you are seeing is normal (a bit low though, but within spec).

  • Nothing connected to pins... I just test it. Is it should be 5v? Is it normal that I get 4.8v when nothing connected? – emj365 Apr 16 '15 at 16:30
  • It should be very close to the voltage of the 5V source, whether a regulator or the USB connection. – Ignacio Vazquez-Abrams Apr 16 '15 at 16:34
  • Thanks. I mean I don't think so 4.8v is very close to 5v. Hope it's fine when I play with it, hope components will work with it. – emj365 Apr 16 '15 at 16:39
  • 5% is a reasonable margin for digital supply voltages. – Ignacio Vazquez-Abrams Apr 16 '15 at 16:41
  • The Yun has no voltage regulator, so the 4.8V instead of 5V is due to the PC or USB plugpack used for power. – DaveP Apr 20 '15 at 12:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.