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Replace revision 1 nrf51822 with revision 3 nrf51422

muhkuhns

Hello,

I ordered some modules and expected them to be based on revision 2 nRF51822.. But they use Revision 1. Now I am struggling getting my Code from the nRF51-DK to work on them. (See this Post.)

So I was asking myself, maybe I could desolder the chip on the module and replace it with the chips that came with the DK...

Looking as a novice at the schematics of my module and the nrf51422 reference layouts I would say it could work.. But before I garbage the chip I would like to hear some opinions from you.

The pulldowns on the SWD pins shouldn't be a problem, or?

BLE Micro Schematic.pdf - Wiki

nrf51x22_qfac_dcdc_reference_schematic.pdf

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  • 0

    Whether or not the chips are pin-compatible and require the same external components exactly you could determine reading the specs, you might get away with it, or ask Seeed micro whether or not they had to change the board for the Rev 3 chips.

    That's hardly the point however. Desoldering and re-soldering a QFN48 package by hand is incredibly hard, doing it without wrecking the board is even harder. You need a hot air gun, a jig, preferably some kind of magnification, solder, flux, a temperature probe and a steadier hand than a brain surgeon. Unless this is a skill you already have, and you may, it's going to be next to impossible.

    You should really go give seeed a hard time about this whole thing and try to get them to ship you some rev 3 boards, or find another board out there, although I would expect many are still rev 2. Or use the SDK which works with rev 1 boards. What is in the latest SDK you absolutely must have for the project, people quite successfully shipped products based on rev 1 chips and the 6.x SDK, nrf51 series was successful long before rev 3, or even rev 2.

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  • 0

    Whether or not the chips are pin-compatible and require the same external components exactly you could determine reading the specs, you might get away with it, or ask Seeed micro whether or not they had to change the board for the Rev 3 chips.

    That's hardly the point however. Desoldering and re-soldering a QFN48 package by hand is incredibly hard, doing it without wrecking the board is even harder. You need a hot air gun, a jig, preferably some kind of magnification, solder, flux, a temperature probe and a steadier hand than a brain surgeon. Unless this is a skill you already have, and you may, it's going to be next to impossible.

    You should really go give seeed a hard time about this whole thing and try to get them to ship you some rev 3 boards, or find another board out there, although I would expect many are still rev 2. Or use the SDK which works with rev 1 boards. What is in the latest SDK you absolutely must have for the project, people quite successfully shipped products based on rev 1 chips and the 6.x SDK, nrf51 series was successful long before rev 3, or even rev 2.

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  • 0 in reply to RK

    Thank you for your honest answer! The problem is my university didn't bought directly from Seeed but a german distributor who is already out of stock. And you only have the 14day return guarantee as a private buyer..

    We have (nearly) all the tools you mentioned. And for the steady hand I got a friend. But still you are right of course. And therefore this IS a option I take into consideration, but not my first preference.

    I couldn't find a single 3rd party board based on revision 3. Only one company from switzerland is testing one at this moment as far as I could get the information.

    I were ok with revision 2, that's why I did my best to get some (from germany so university can buy them) but it failed.

    I were going to test the older SDKs starting today. But it is of course lots more work because as far as I have seen many functions have changed since them... Also I ran into troubles when I wanted to try it out yesterday.. Missing Devices... SDK4/5/6.. Gotta find me the right starting guide which explain what software I need and how to install it.

    Having to use SDK8 for the central (nrf51-dk) and older SDK for the 4 peripherals isn't close to ideal.

  • 0 in reply to RK

    Well... I suppose I qualify as a person with some experience in soldering / desoldering QFN packages, but I can't say I find it too difficult (and I have trained others to do it). Getting the chip off is easy enough, hot air gun and decent tweezers. After you got the chip off make sure that the remaining solder on the pads is reasonably level (similar amounts of solder on each pad). Add a thin layer of good quality tacky flux (something like AMTECH RMA-223) on all the pads and place the new chip on with your tweezers. Have a look at the sides of the chip from all sides nudging it gently with the side of the tweezers until all the pads line up well enough (I'm short-sighted so I can just look over the top of my glasses rather than needing magnification, ymmv). Then heat it up with the hot air gun (decent temperature, not too much flow) until reflowed.

  • 0 in reply to RK

    And indeed the chips will work just fine with the same external components.

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