kicad-developers team mailing list archive

[Lorenzo Marcantonio <l.marcantonio@xxxxxxxxxxxx>]

On Thu, 2 Sep 2010, Brian F. G. Bidulock wrote:

> Looking at an entry for a BGA below (wrapped) from BGA7351B.plb09

Ahem... I've only done CHP component till now :D

> Many of the XML'ish attributes appear self-explanatory: (all decimal
> units appear to be in MM, and integer units are 10 nanometers.  These
> probably correspond to fields in the calculator.

Exactly. There's a risk that the decimal unit are in the 'configured
unit', but IPC seems to do all its work in metric.

>  <Stg_Pf
>     dflt="1" <- default is pin 1?

No, it's the 'use default' not 'user' radio button

>     cyd_xs="1" <- courtyard excess?

Exactly, nominal for BGA is 1mm

>  BGA; <- specifies format of following fields...
>      1; <- ????

It seems a revision level indicator. For CHP it's always 0 except for
CLED which were added later and have 1. It seems that the viewer ignores
it.

>      0 1 4 1 4 1 26 3 7 1 3 1 3 1 2 1 1 1 1 1 2 1 3 1 3 1 7 3 26 1 4
>        1 4 1; <- some way of spec'ing the 21 missing balls in the grid?

Probably yes. But I prefer to analyze first the 'easy' component to
better get in their mindset. Also BGA have different rules (they don't
have fillet targets, only pad size proportions depending on pitch).

> Well, that's the idea anyway....

You're right. I'm doing the analysis component by component, you have to
be patient :D

--
Lorenzo Marcantonio
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