When does a down begin

[mtridge]

Does a down begin at the ready or when it is snapped?, I could not find clear answer in rule book.

Also the background to this question is the whole New Mexico mess where the refs started the clock after a penalty. I saw this argument but I'm not convinced

: Rule 3-3-3 -Me: I was. ... 3-3-3 A period must be extended by an untimed down if during the last time down of the period there was a foul by either team and the penalty is accepted

the argument made was that since there was a penalty on the last play of the game the game should have been at least extended one untimed down.

However, if a down starts at the ready and no at the snap then there was no penalty during the last time down and therefore the situation was handled correctly.