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Opinions Requested - Small Propeller (P8X32A-D40) prototyping board idea — Parallax Forums

Opinions Requested - Small Propeller (P8X32A-D40) prototyping board idea

WossnameWossname Posts: 174
edited 2011-07-11 13:25 in Propeller 1
As part of learning the DipTrace suite of software, I decided to design a small, convenient PCB layout for a Propeller prototyping board, analogous to the Arduino board except with off-board FTDI (via the Prop Plug or similar).

I've finished the initial design - the schematic is basically just the one from the Propeller manual, but also has a 3v3 voltage regulator circuit on the board too.

My question is this: Is it worth me doing anything with this design such as making it open source under the Creative Commons licence (Github was suggested to me as a means of distributing it)? Would anyone be interested in such a thing or is it a bit pointless?

I only did it for a bit of fun but I did build a perfboard version of it and I use it quite a lot. The Layout for the proper PCB design is 1.65" x 2.575" - so it's substantially smaller than the Arduino and it's all SMD components apart from the Propeller PDIP chip itself, which is mounted in a socket.


It's not particularly technically accomplished or anything (it's only a 2 layer board), it didn't take long to create but perhaps someone would find such a thing useful.

I still have a bit of cost optimising to do but I reckon this design could be built (think PCB Cart or similar fabrication company) and populated for less than $16 including the Propeller chip.


So yeah, I'd like to know what people think of this idea.

Comments

  • LeonLeon Posts: 7,620
    edited 2011-07-10 03:42
    I designed and made something like it for my own use on a single-sided home-made PCB. It had a prototyping area. It was much bigger, though.

    I'd post it, it looks quite neat and someone might want to get it made.
  • __red____red__ Posts: 470
    edited 2011-07-10 07:34
    Welcome Wossname,

    It's a small world - I've already been reading your blog and +1'ing your posts on it :-)

    I would love to see your design. Right now I'm doing the exact same thing with a view to turning it into a hackerspace business card. Did you go through-hole or smt?

    I publish my designs on github here: http://github.com/redvers/isokeyboard
  • HumanoidoHumanoido Posts: 5,770
    edited 2011-07-10 08:01
    I would also like to see your design. Open source designs for the prop can be very useful. I envision a series of boards, open source to create the boards, where we can pick and choose from a "catalog," based on our requirements.
  • WossnameWossname Posts: 174
    edited 2011-07-10 08:10
    Hi Red, thanks for giving me the idea in the first place :)

    I'll try to get it uploaded to github later on then. What format should I upload? I'll put the Diptrace files on there of course but should I also add the Gerbers and bill of materials?

    I've not generated Gerber output before so someone will have to let me know if I've done it wrong :)

    I'll drop a link on here when it's up, thanks for the input guys.

    The Propeller seems to have a pretty friendly community grown up around it. Much more so, I'd say, than the Arduino. Long may it remain :)
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-07-10 09:53
    Wossname,

    Yes, welcome to the forums.

    I also like your Propeller board.

    I know you said you followed the schematics in the manual but one thing I've read many times on this forum is that there should be a 0.1uF decoupling capacitor very close to each Vdd pin on the Prop. Apparently these caps are even more important if one overclocks their Prop but even at 80MHz they are strongly recommended.

    As usual, the more Propeller board options, the merrier.

    It would also be a good idea to have the other forum members take a look at the copper layers of your board. There are several members with a lot of circuit board designing experience here.

    Duane
  • __red____red__ Posts: 470
    edited 2011-07-10 10:27
    Duane Degn wrote: »
    As usual, the more Propeller board options, the merrier.

    It's funny because this is the exact thing that excites me about the propeller community so much more than the Arduino community. The two schools of thought:
    1. A single physical design that everyone can interface to and builds "shields" for.
    2. A plethora of designs from which to choose from with a community willing to help you roll your own.
    It reminds me of the philosophical discussion I see in the Open Source Software community where people consider code-forking to be disrespectful or harmful. It really isn't. It's a wonderful thing because with forking we get diversity, choice and competition.

    The problem with "standard" designs is that they quickly become straight-jackets.
  • kwinnkwinn Posts: 8,697
    edited 2011-07-10 10:45
    Both schools of thought have their own advantages and disadvantages, and both can and should co-exist.
  • WossnameWossname Posts: 174
    edited 2011-07-10 11:04
    Hi Duane,

    I'd love to have some experienced board designers give me some tips on how the design can be tidied up, I'm sure I've made a whole raft of newbie errors. I didn't put any decoupling caps in this first spin, but I'll put it on the wish list for the next revision.

    Anyway, I've released "Protopeller" (as I'm calling it, can't believe that name wasn't taken already!) in it's design form here:

    http://github.com/AdamWard/Protopeller

    It's under the CC-BY-SA 3.0 licence, so it's nice and easy to play with :)

    I welcome any and all creative criticism and I will be glad to credit anyone in the "credits" file in the main repo.

    I'm planning to figure out alternative file types that I can add to this repo - I appreciate that not every hobbyist can afford expensive tools like DipTrace - so it would be valuable to get this design exported into different formats such as Gerber, netlists, gcode and anything else that anyone wants. All suggestions welcome.
  • LeonLeon Posts: 7,620
    edited 2011-07-10 11:40
    The crystal frequency should be 5 MHz, not 80 MHz.

    I don't use Diptrace, so I could be wrong, but the copper pour doesn't seem to be connected to ground.
  • WossnameWossname Posts: 174
    edited 2011-07-10 11:54
    Leon, can you please clarify what you mean? I don't think I mentioned the crystal in my project files.
  • LeonLeon Posts: 7,620
    edited 2011-07-10 12:00
    It's on your schematic.

    It's not usual to use buses for supplies on schematics, just use short connections to a Vcc or Gnd symbol. I've attached one of my schematics.
    1024 x 493 - 44K
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-07-10 12:03
    Wossname wrote: »
    I've released "Protopeller" (as I'm calling it, can't believe that name wasn't taken already!)

    I like "Protopeller." I wish I had thought of it.


    Duane
  • JonnyMacJonnyMac Posts: 9,208
    edited 2011-07-10 21:36
    What version of DipTrace are you using? I have the latest (2.1.9.5) and it complains the the files are the wrong format.
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2011-07-10 23:17
    Nice little layout. I just took a quick look, and your copper pours need to be tied to the ground net (on the connectivity tab when you finish a pour). Also, you have a couple "islands" that are surrounded by traces and thus won't be able to be tied to ground. (I accidentally left a tiny one on my M44D40+ module as well). Not critical in most usages of the propeller, but not preferred from a design perspective. You can adjust clearance settings when you finish a pour and that will help prevent islands from being created.
    I'm planning to figure out alternative file types that I can add to this repo - I appreciate that not every hobbyist can afford expensive tools like DipTrace - so it would be valuable to get this design exported into different formats such as Gerber, netlists, gcode and anything else that anyone wants. All suggestions welcome.
    DipTrace does have a free version and your design should easily fit within the requirements for the free version. However, exporting a clean set of gerber files would also allow anyone to have the board made by any fab shop and they won't have to even touch the design files.

    Lastly, your perfboard version is fantastic! Excellent layout work.

    @jonnymac: FYI, I am using 2.1.9.3 and it came right in.
  • PublisonPublison Posts: 12,366
    edited 2011-07-11 04:35
    JonnyMac wrote: »
    What version of DipTrace are you using? I have the latest (2.1.9.5) and it complains the the files are the wrong format.

    I'm having the same problem as Jon. I'm using (2.1.9.0)
  • WossnameWossname Posts: 174
    edited 2011-07-11 05:03
    I wonder if it's getting corrupted when I upload to github. I can't remember what version I'm using, I'll have a look when I get home.
  • WossnameWossname Posts: 174
    edited 2011-07-11 09:40
    I'm using 2.1.0.7 (full version). I only bought it a couple of weeks back, did I waste my money on an old version?
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2011-07-11 09:45
    That's really odd, I am using 2.1.9.3 and it came right in. I have 2.1.0.2 at work and it came in no problem as well. However, I do have the Full Edition in both cases. Maybe that has something to do with it? Don't know why it would.

    p.s., no you did not waste your money. You can upgrade to the latest version (2.1.9.5) for free and when 2.2 is released, all 2.x users get it for free as well.
  • PublisonPublison Posts: 12,366
    edited 2011-07-11 10:11
    Are you guys running the Beta software? I just found this on their forums:
    Yes, beta files are not compatible with ver.2.1 as we changed file formats. But you can use Diptrace ASCII format to transfer files from beta to 2.1.

    I'm running BETA 2.1.9.0
  • PublisonPublison Posts: 12,366
    edited 2011-07-11 10:21
    Just installed Non-Beta 2.1.0.7 (Non-Profit). Still same problem. Might it be the 300 Pin limitation?
  • WossnameWossname Posts: 174
    edited 2011-07-11 10:45
    Ok I'll upgrade my software at some point soon.

    @Leon / @WBAC: How come it's supposed to be a 5MHz crystal? Does that get multiplied up to 80Mhz internally?

    @Publison: There's way less than 300 pins in this design.

    It sucks that people can't open it, I'll try to do something about that. Stay tuned.
  • LeonLeon Posts: 7,620
    edited 2011-07-11 11:08
    The oscillator has a 5 MHz crystal and is running at 5 MHz. The 80 MHz clock (if the PLL is enabled) is internal, it depends on the software that is running.
  • WossnameWossname Posts: 174
    edited 2011-07-11 13:25
    I've done a quick update to the design, fixed some of the copper pour problems, removed power buses in favour of normal symbols. I've also added some ASCII design files in the hope that people can open them this time. Also there's an ncdrill file.
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