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CC3000 Boot sequence

Jean-Christophe Billard
Intellectual 730 points

Hello,

I am facing some issue with cc3000's startup sequence that is:

It is about a custom board design, so it might be an chip soldering issue (not a design one as it was verified multiple time and almost the same as others that work).

When WLAN_EN goes high after a valid powerup sequence, SPI_IRQ follows and rails to VCC_IO. However, I never see it going low anymore telling that the module is ready. Any thoughts on the potential issues?

BTW, they are modules bought from mouser/digikey and I wonder if it should be any patch to be downloaded to the module before first use?

Thank you very much for your answers.

Regards,

Jean

  • 0
    Expert 1140 points

     Hi!

     We had something like this. This was due to bad CC3000 soldering. Perhaps EEPROM pins are not connected. That's why CC3000 reacts on WLAN_EN but probably fails to  boot.

  • 0 in reply to Dmitry Bodnya
    Intellectual 730 points

    Hi Dmitry,

    Thanks a lot for the feedback. It seems it is somewhat not possible to rework the protos as I have some polyamid parts just next to it and they burn even just with hot air solder. Do you have a special process for soldering those parts?

    From my experience, what the only way I could be successful was to pass a first time the boards on reflow oven, with paste on it so a small soldering menisc would appear, and in a second run, I would go with the chip on top. 

    However, going with only flux + soldering paste with directly the chip on top it fails constantly.I am considering using very low melting point paste, so the reqork would be easier.

    Have a great day.

    Jean

  • 0 in reply to Jean-Christophe Billard
    Intellectual 730 points

    Well I insisted and it works, was a soldering issue indeed.

    Well it's not really pretty (I had some nice looking white plugs that have now some sun burns), but hey, that's what we wanted right?

    In fact I use ROHS chip quik soldering paste. But I would recommand lead based paste for this kind of flat boards, as it is somewhat harder to reach the melting point for the whole surface.

    Regards,

    Jean

  • 0 in reply to Jean-Christophe Billard
    Guru 12050 points

    A paste stencil is nearly a must, without it I only get 70% reflow success rate.
    http://ohararp.com/product/kapton-stencil-8-5x11/

    Putting a penny on top on module to weight down a little while reflowing is what I do sometimes.

    Let I cool before moving pcb, as you can not see if you disrupted ic's parts inside cc3000module by moving pcb to early.

     

  • 0 in reply to Tony Philipsson
    Intellectual 730 points

    Nice tip! I did not thought about the penny, that's funny!

    Well, from my prospective after a week of calibration on many proto, here are my "conclusions":

    The best way to have nice solder, is definitely to do it using hot air gun, and while you are at the fusion point, gently push down and then release for few cycle the chip, so all the paste will finally agregates and you'll get a nice solder. Make sure not move the shield, as Tony says, you do not want to disrupt the IC's inside the module.

    Now the issue is that if you do not have a controlled and dry environment, you'll have some oxidation on the shielding, which is not really good looking.

    Using, reflow oven for me gives too much uncertainty, but I think that with a soldering paste of lower fusion point should give better results.

    Regards,

    Jean