[PCB_FORUM] Re: Where is package to package constraint set?
- From: "Austin Franklin" <allegrolist@xxxxxxxxxxxx>
- To: <icu-pcb-forum@xxxxxxxxxxxxx>
- Date: Fri, 21 Mar 2008 15:25:55 -0500
Hi Michael,
Thank you VERY much for the nicely detailed explanation. It was very clear
and I believe I actually understood it. Not having any feedback in move
mode is a problem. I could turn on all the boxes, and visually use them, I
guess.
Regards,
Austin
> -----Original Message-----
> From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
> [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of Baumstark
> Michael-EMB043
> Sent: Friday, March 21, 2008 11:06 AM
> To: icu-pcb-forum@xxxxxxxxxxxxx
> Subject: [PCB_FORUM] Re: Where is package to package constraint set?
>
>
> Austin,
>
> Cadence Allegro Editor supports two modes of component spacing rules
> checks. The traditional mode uses only the packages' Place_bound (top
> and/or bottom). When the Package to Package rule check is turned on
> under the setup constraints GUI you can have DRC checking on for this
> use model. As we know this checks to tangency or encroachment of the
> place bound shapes, or allows encroachment providing there exists
> sufficient cavity space under a component, using the Package_height_min.
> for constraining the cavity space. But that requires a higher order of
> DFA awareness beyond the basics of the normal pick and place clearances
> for assemblies. Most companies have tailored their place-bounds to
> function acceptably with this simplistic mode.
>
> The second mode of checking has been around for a few years with Cadence
> and it is established in the setup DFA spreadsheet GUI under your setup
> pull-down menu. This is the more sophisticated mode of operation but the
> right mode of tool operation when dealing with "Design for Assembly"
> requirements typically needed for mass-production designs. This mode
> sets up additional clearances from different component_types, with 3
> adjustment settings: side-to-side, end-to-end and side-to-end (I forgot
> the exact order as the numbers are listed in the matrix. This rule
> checking is turned on within this GUI only, so don't get it confused
> with the traditional package to package rule checking in the main
> physical rules GUI.
>
> Additional notes: You need to have appropriate work done within your
> library of parts to properly enable the DFA package to package checking
> use model. For example, your footprints must have the appropriate
> component_type=value established. Cadence established two new layers
> called DFA_placebound_ (top and/or bottom) just for this DFA
> implementation. But the traditional Place_bound (top/bot) features will
> be used if there does not exist features on the DFA_PLbound_t/b layers.
> Also worthy of mention is the real time heads-up display of DRC checking
> when using the DFA use model. A circular bubble displays when you are at
> the limit of your DFA spacing interaction and two small DRC flags
> display on the bubble once you have encroached inside that limit. This
> heads-up display mode only works in the Place Manually mode and not with
> the Move mode of operation. The traditional DRC flags still function as
> usual, post click, but using a D-C flag to indicate a DFA checking
> component spacing violation.
>
> Hopefully, this helps in the explanation of what is happening under the
> hood just a little bit, more better, than simply being able to turn the
> checking switch on. :)
>
> Have a great Friday, it's a Good one.
>
>
> Sincerely yours,
>
> Michael Baumstark
>
> Sr. Staff Electrical Engineer / PCB Design, CID+
> Motorola - Advanced Product Technology Center
> 8000 West Sunrise Blvd. Mail Stop: 8E8
> Plantation, FL USA 33322-9947
> Intra: http://rprc.mot.com ; http://pcbadvisor.mot.com
> web: http://www.motorola.com
> --------------^------------------^-----------------^------------------^-
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> >---^-.--- >---^-.--- >---^-.---
> Motorola Internal Use [ ]
> Motorola Confidential Proprietary [ ]
>
>
>
> -----Original Message-----
> From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
> [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Austin Franklin
> Sent: Thursday, March 20, 2008 2:47 PM
> To: icu-pcb-forum@xxxxxxxxxxxxx
> Subject: [PCB_FORUM] Where is package to package constraint set?
>
> Hi,
>
> For the life of me, I can't find where the default package to package
> constraint is set. Where is it set?
>
> Regards,
>
> Austin
>
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