Seeking PADs  .pcb file format specification to write decoder for OpenBoardView - Page 1
Forum section: electronics / general

author: Inflex
author_rank: Regular Contributor
timestamp: January 06, 2017, 05:04:16 am
content: Hi everyone,Wondering if anyone had access to the file format specification for the PADs .pcb file format ( looks like a database type format from initial inspection ) ?I'm asking because I want to write a decoder for it so I can add it as another format that OpenBoardView can decode (http://openboardview.org).Regards,Paul.

author: vzoole
author_rank: Regular Contributor
timestamp: January 06, 2017, 03:13:09 pm
content: Hi!What kind of format it can handle already?

author: Inflex
author_rank: Regular Contributor
timestamp: January 06, 2017, 03:17:10 pm
content: Quote from: vzoole on January 06, 2017, 03:13:09 pmBRD (A couple of different variants)BDVBV (but needs to be converted first separately to BVR due to licence issues with the MS Access DB library)FZ (encrypted, plain, zipped)CASTPADs .pcb would be nice because there's a couple of repositories of iPhone boardviews in that format and a lot of people are wanting to be able to view those.

author: vzoole
author_rank: Regular Contributor
timestamp: January 06, 2017, 03:22:22 pm
content: What is BRD format?Like orcad and eagle *.brd files?

author: AndyC_772
author_rank: Super Contributor
timestamp: January 06, 2017, 03:24:30 pm
content: PADS will export an ASCII file format which is much more developer friendly.It's still a 'native' format, so there are no issues with exporting a design to .asc and re-importing it. Think of it as a human-readable version of the .PCB format.If you really need to parse .PCB directly, then it may be helpful to get the same design in both .PCB and .ASC formats, and use one to help understand the meaning of the other.

author: Inflex
author_rank: Regular Contributor
timestamp: January 06, 2017, 03:30:32 pm
content: Quote from: vzoole on January 06, 2017, 03:22:22 pmI do have an Eagle decoder planned (not a major issue as it's a nice XML format which is entirely readble)There's two types of BRD files supported;Most common is the encoded / plain with a 4-byte leading signature of 0x23, 0xe2, 0x63, 0x28. In the decoded form they have sections like "var_data:" and "Format:", this is what most Macbook BRD files are available as (as used by Louis Rossmann).Second type is TOPTEST BoardViewR4 file formatWe now have a 3rd BRD format that we've got to decode ( Cadence BRDhttps://github.com/OpenBoardView/OpenBoardView/issues/62), and of course the Eagle one as mentioned before.

author: Inflex
author_rank: Regular Contributor
timestamp: January 06, 2017, 03:32:27 pm
content: Quote from: AndyC_772 on January 06, 2017, 03:24:30 pmThat would be astoundingly useful, yes. At this point we've not had a pair of files like that submitted, but we do already decode the .ASC format (https://github.com/OpenBoardView/OpenBoardView/issues/45)

author: GreggD
author_rank: Regular Contributor
timestamp: January 06, 2017, 04:12:59 pm
content: ftp://ftp.freecalypso.org/pub/CAD/PADS/pdfdocs/Ppcb_ASCII.pdfAscii format can be inches, mills, mm or native units.

author: vzoole
author_rank: Regular Contributor
timestamp: January 06, 2017, 04:21:37 pm
content: Quote from: Inflex on January 06, 2017, 03:30:32 pmThanks for info!

author: Inflex
author_rank: Regular Contributor
timestamp: January 06, 2017, 04:39:08 pm
content: Quote from: GreggD on January 06, 2017, 04:12:59 pmThanks for that. A shame they have to also have the binary .pcb file to make things more complex, but at least this is a good hard reference to have on hand.

author: Inflex
author_rank: Regular Contributor
timestamp: January 06, 2017, 04:40:47 pm
content: Quote from: GreggD on January 06, 2017, 04:12:59 pmIf you, or anyone, can provide the same board in both formats, that would be an excellent resource to work from.Potentially the simpler the board the easier (within reason, ie, maybe a dozen parts)

author: PCB.Wiz
author_rank: Super Contributor
timestamp: January 11, 2017, 02:35:07 am
content: Quote from: Inflex on January 06, 2017, 04:39:08 pmI think the Binary exists merely because it can load faster.I'd be wary of chasing 3rd party Binary read, as that changes with every release, and is a lot of work, whilst ASCII export is in all seats, and with a wide range of export format.ie PADS ASCII is stable, and highly version portable, and you can give meaningful error messages when reading it.

author: Inflex
author_rank: Regular Contributor
timestamp: January 11, 2017, 02:40:11 am
content: Quote from: PCB.Wiz on January 11, 2017, 02:35:07 amI agree, I prefer the ASCII formats as well; that said, there is a compelling reason for me to support the binary version of the .pcb file, is that there are iPhone boardviews available in that format, that single group of .pcb files alone makes having the ability to read the binary version quite a key feature for many people in the industry.Only way around would be to find a .pcb -> ASC converter (since we already read the text version perfectly fine).

author: PCB.Wiz
author_rank: Super Contributor
timestamp: January 11, 2017, 08:08:33 am
content: Quote from: Inflex on January 11, 2017, 02:40:11 amAny license PADS seat can do this, so I'm not quite seeing the problem here ?

author: Inflex
author_rank: Regular Contributor
timestamp: January 11, 2017, 08:37:42 am
content: Quote from: PCB.Wiz on January 11, 2017, 08:08:33 amI don't have a licence (or use) for PADs. That said, thanks for that information, I'll look for someone with a licence to perform the temporary task that'll at least give myself and others time to then work on the binary read version.

author: Inflex
author_rank: Regular Contributor
timestamp: May 03, 2017, 01:05:53 pm
content: Bumping this. Been nearly 4 months now, no success yet.Being able to get my hands on the PADs binary .pcb file format would be of great assistance.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: May 03, 2017, 08:56:14 pm
content: Quote from: Inflex on May 03, 2017, 01:05:53 pmAs I mentioned above, chasing BINARY files is both a lottery and a moving target.You can be almost certain each majour version release, will fiddle with the binary, andMentor have just released PADS Maker- that is now BINARYonlyand no ASCII, and they have changed the Binary deliberately so you cannot load into PADS Standard (or vice versa).Because they are somewhat paranoid about closing customer's pathways down, the Binary format of Maker will likely have added protections.All of this, and it is still called .PCB file

author: PCB.Wiz
author_rank: Super Contributor
timestamp: May 03, 2017, 11:37:36 pm
content: Quote from: evb149 on May 03, 2017, 09:09:50 pmThat's a good point :ODB++ would be a better pathway, as at least that is intended for data interchange.Even the extremely closed PADS Maker can export ODB++There are ODB++ viewers, so you can check the content.eg this one,https://www.mentor.com/pcb/downloads/odb-plus-plus-vieweris not small, but seems to work..Contains netlist, refdes, and footprint information.

author: Inflex
author_rank: Regular Contributor
timestamp: August 22, 2017, 01:44:17 pm
content: Quote from: evb149 on May 03, 2017, 09:09:50 pmThis is the approach we're trying to go for currently in the absence of any real chance of obtaining any form of a written specification. Even a single example board with perhaps 2 layers, 3~5 parts, 2 or 3 packages, nets and a rectangular outline would most likely provide enough working information but still be small enough to dissect by hand.

author: wedgetail
author_rank: Contributor
timestamp: October 06, 2017, 01:15:34 am
content: Would following files be of any help, PADS and ASC equivalent as I understand it.The layout fits in there some where

author: Inflex
author_rank: Regular Contributor
timestamp: October 06, 2017, 02:32:27 am
content: Thanks for that Wedgetail. It's still a big file (1MB) but perhaps marginally more accessible than the existing ones I've been trying to decode.Definitely hope someone can produce a very minimal board in binary-pcb format for us soon.

author: pigrew
author_rank: Frequent Contributor
timestamp: October 06, 2017, 03:07:06 am
content: I wonder if tapatalk hosting works?Here is a file with two decals. I don't really know how to use pads, so it's pretty basic.I exported the file into many of the available ASC formats. In the middle it added CAM info to the file when I tried to do an export to odb++. I used pads version vX.0.http://cloud.tapatalk.com/s/59d6f2b17f292/pads_simple.zip

author: Inflex
author_rank: Regular Contributor
timestamp: October 06, 2017, 03:19:56 am
content: @pigrew If I could "like" your post 1000 times I would!That's finally a genuinely usable file with a chance of decoding things.Many thanks again.