Back Annotating Printed Circuit Boards
Guy Macon
(From a discussion in comp.arch.embedded about exporting a
parts list from LTSpice in Pads2000 Format into FreePCB,
as opposed to a more integrated product such as Kicad.) [1]
Many designs have R1 next to R2, etc. on the schematic, making
it easy to find R2 on the schematic but hard(er) to find R1 on
the board. I like to put R1 next to R2 on the board, making
it easy to find R2 on the board but hard(er) to find R2 on the
schematic.
In production, a technician is far more likely to start with
R2 on the schematic and then look for R2 on the board to hook
up a meter or scope probe than he is to start with R2 on the
board and then look for R2 on the schematic. He usually only
does the latter when he starts with a burnt component.
An assembler starts with a parts list instead of a schematic,
and then looks for the parts on the board, so once again
having R1 next to R2 on the board is better.
It's more work for the engineer to back annotate, but it
is work that is done once, with the benefit to production
happening again and again as long as they make that board.
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[1] References:
LTSpice:
http://www.linear.com/designtools/software/#Spice
FreePCB & FreeRouting:
http://www.freepcb.com/
http://en.wikipedia.org/wiki/FreePCB
http://www.freerouting.net/
http://en.wikipedia.org/wiki/FreeRouting
Using LTSpice as schematic capture for FreePCB:
http://home.comcast.net/~andy_c_public/ltspice_freepcb_1.htm
http://diyhifi.org/forums/viewtopic.php?f=15&t=1121&view=next
KiCad EDA (Electronic Design Automation):
http://freshmeat.net/projects/kicad/
http://www.uchobby.com/index.php/2008/01/15/kicad-free-and-open-source-eda-tool/
http://kicad.sourceforge.net/wiki/index.php/Main_Page
http://kicad.sourceforge.net/wiki/index.php/About_KiCad
http://xtronics.com/reference/kicad.html
http://wiki.xtronics.com/index.php/Kicad
http://www.gipsa-lab.inpg.fr/realise_au_lis/kicad/
http://sourceforge.net/projects/edif2kicad/
Also see:
http://www.fritzing.org/development/market-overview
--
misc.business.product-dev: a Usenet newsgroup
about the Business of Product Development.
-- Guy Macon <http://www.guymacon.com/>
--
misc.business.product-dev: a Usenet newsgroup
about the Business of Product Development.
-- Guy Macon <http://www.guymacon.com/>