Pin 1 denote is optional or mandatory?

[noisepic]

Sorry for the seem stupid question.
​For me it is not problem in debug or testing, but does it have any problem if a package lack of Pin 1 denote?

Thanks.

[robertferanec]

I always mark Pin 1 - it is useful and it can prevent possible errors when your board is assembled.

[noisepic]

When send to pcb assemble also have data of "direction" and automatically done by SMT machine. Mark pin 1 is still necessary?

[Luca]

Maybe you mean the "direction" of components inside the reel. Of course the assembly house check this kind of information but I suggest to mark pin 1 for all components. It's very usefull for the assembly process and for check it. It's also very usefull under test you board, especially if you don't do it personally.

[robertferanec]

When send to pcb assemble also have data of "direction" and automatically done by SMT machine.

People who are setting up the machines need this information.

You definitely need to place pin 1 information on assembly drawing, theoretically you do not have to use it on Silkscreen, but if you for example do not mark Pin1 on connector, then users of your board can plug in the cables wrong way and damage your board. It is good practice to mark pin 1, because it can help many people.