Grbl not responding hold/cycle commands

[cearza]

Hi! I would like to pause a carve in my cnc. I flashed my arduino mega with grbl845mega2560 and I installed momentary buttons for reset,feed hold and cycle start on pins A8,A9 and A10 respectively (according with the pin map on the hex file).But they are not working! can you please give me a clue on how to achieve this? Thanks