The 121 pin MAPBGA package (MK22FN256) has several 'NC' pins on the periphery of the package.
Routing would be made much easier if we could either route through these pads or not populate the pads at all.
Are either of these options possible?
For NC pins. you can route through when you layout. For pins which have function but no used, you cannot route through.
Hope my reply can help you.
That is very helpful.
However can I ask you to confirm that I can route through NC pads because I have since found this thread which seems to disagree:
NC pins on Kinetis K20 based MK20FN1M0VMD12 quick easy question
Maybe I wasn't very clear...
I found this thread which suggests that 'NC' pins on the MK20 parts are used for internal testing, and so should not be connected to anything on the board.
But the answer in that thread sounds very generic. So I am looking for confirmation.
I am using the MK22FN256 part and there are several NC pins on the periphery.
Are these pins connected internally?
If not, then I can route through them and it makes life much easier.
If they are used for testing etc then of course I will need to avoid them.
At my blog there are links to books on PCB layout including BGA routing: http://blog.softwaresafety.net/2010/03/survival-is-not-mandatory-right-first.html
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