i can't get attiny84 working

Hi, i've used arduino to program a lot of ATtiny85, no problems. Now i need more pins, then i need attiny84. Connect it to my arduino uno, recheck the connections, select Attiny84 8mhz in boards, load blink example ... 1- burn bootloader = no errors (the same output messages with attiny85) 2- upload sketch = no error (same output messages with attiny85) and the led is not blinking. Check again, change to 1mhz for test ... same result. Have test with 3 attiny84, with an attiny85 (and selecing the board) it's working. Why i can't get my led blinking with attiny84?

Maybe you're looking at the wrong pin.

Grab a multimeter and look at all the pins to see if one is going HI/LO.

done, all pins LO :(

Try different pins…try direct port access.

DDRA = 255;
PORTA = 0;
delay(1000);
PORTA = 255;
delay(1000);

That will make 8 pins go LO/HI

juanmol: Hi, i've used arduino to program a lot of ATtiny85, no problems. Now i need more pins, then i need attiny84. Connect it to my arduino uno, recheck the connections, select Attiny84 8mhz in boards, load blink example ... 1- burn bootloader = no errors (the same output messages with attiny85) 2- upload sketch = no error (same output messages with attiny85) and the led is not blinking. Check again, change to 1mhz for test ... same result. Have test with 3 attiny84, with an attiny85 (and selecing the board) it's working. Why i can't get my led blinking with attiny84?

-try another attiny84 core -check fuses are correct -try avdude -check reset pin is high

Here are some suggestions.