Single-Board Universal Module

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07 Oct 2014 13:29 #25990 by moss
Replied by moss on topic Single-Board Universal Module
@PB
You could probe the RF signal flow with a spectrum analyzer by just touching the tip to a solder joint. The power level will not be accurate, but you can easily spot gain on an amp by comparing input to output. The readings will probably be 6 dB low. As a "probe" a RG405 semi-rigid type cable/pigtail works fine, the center lead is steel, so it holds up well. Make sure your analyzer can handle DC, or else use a DC block.

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07 Oct 2014 15:27 #25993 by PhracturedBlue
Replied by PhracturedBlue on topic Single-Board Universal Module
That is a good idea. I don't have any spare RG405, but I was able to cut a U.FL to SMA cable, and get a lead from that. I'll see if I can learn any more later tonight.

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08 Oct 2014 01:38 #25999 by PhracturedBlue
Replied by PhracturedBlue on topic Single-Board Universal Module
Well, I'm pretty convinced the switch isn't working. The ctrl pins seem to be ok, and the switch has 3.3V and GND. The individual circuits for the cyrf, a7105 and cc2500 are working. The NRF is not, but it is quite likely that is a software issue. I can't tell whether Im getting full power from the transceivers, however, the signal is significantly stronger if I connect to the relevant input pins of the switch than after it for each of the 3 chips. I'm wondering whether I cooked it when attaching the blocking Cap (it does appear a bit melted I guess I touched it with the iron).

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08 Oct 2014 02:20 - 08 Oct 2014 02:31 #26000 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
Well, that's encouraging. It'll be fairly easy to change with your hot air gun.


What were the logic levels you measured on the control pins? The switch has a 2.5-3V logic high level, and TTL port output voltage for the MCU is listed as min 2.4v. I'm not at all familiar with the ST MCUs, so please forgive me if I'm way off base; just thinking out loud hoping it may prompt something.
Last edit: 08 Oct 2014 02:31 by mikemacwillie.

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08 Oct 2014 02:54 #26001 by PhracturedBlue
Replied by PhracturedBlue on topic Single-Board Universal Module
all logic levels are 3.3V

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08 Oct 2014 02:56 #26002 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
Ah, good. Probably just a bad part then. :)

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08 Oct 2014 03:07 #26003 by octagon
Replied by octagon on topic Single-Board Universal Module
just to be sure, the logic of the switch should turn on the same port as the corresponding RF-source :P

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08 Oct 2014 04:20 #26004 by PhracturedBlue
Replied by PhracturedBlue on topic Single-Board Universal Module
of course. And I've verified it does.
On the next revision of the board, I'm considering changing to a Peregrine PE42641. I don't like the fact that the Skyworks part is essentially a single-source part. Sadly the skyworks and Peregrine are not pin compatible (though very close). The skyworks is a little cheaper and has better insertion loss though.

I also considered using 3 SPDT switches (like a PE4259). These parts are generally easily available, though I've not found anything other than the Peregrine parts that support a single-=line control in a sc-70 package.

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08 Oct 2014 16:52 #26010 by PhracturedBlue
Replied by PhracturedBlue on topic Single-Board Universal Module
well, I made things worse.
initially I removed it and replaced a new one and got identical results. I then thought maybe I didn't get a good solder joint, so I attempted to use an iron to ensure connectivity. now i have even worse transmission through the switch. I hate these qfn packages. it is next to impossible to proble them to verify connectivity

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08 Oct 2014 16:58 #26011 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
Do you have a flux pen / liquid flux? If you do, you can apply a decent amount of it, and drag your tip along the edges of the pins. As long as you don't have too much solder on there, you'll get reasonably good joints doing so. Another possibility is excess solder on the thermal pad, bridging to one of the leads under the IC. These ones are a nightmare to find. Would it be of any benefit if I shipped you one of mine after my new PAs arrive? My RF explorer shipped today, but it probably won't be here for a couple of weeks.

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09 Oct 2014 22:28 #26022 by octagon
Replied by octagon on topic Single-Board Universal Module
QFN parts are fine, if you have the right equipment :-P
Too much solder under the part, and/or no escape path (i.e. enough vias) a center blob can prevent the part from seating on all sides.
If you a apply a little pressure on the part while the solder is liquid, and keep on it until the solder sets you nay overcome those problems.
Too little solder and no contact is obviously another problem.

I don't have a hot-plate so I use a small hot-air "gun", for shrink-tube, plus a Hakko soldering iron, for re-work.

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21 Oct 2014 16:09 #26127 by jens
Replied by jens on topic Single-Board Universal Module
i am a newbee in deviation, and i didn't read the complete thread.
But if i could buy this "universal module", where to buy?

Kind Regards
Jens from Germany
(sorry for bad english)

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21 Oct 2014 16:20 #26128 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
This one is still in the development stage, so unfortunately you can't buy it yet.

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01 Nov 2014 17:34 #26253 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
My PAs are here, as is my RF explorer. I'm hoping to have some time to install the PAs this weekend. PB, is there some test code available for the module that you'd be willing to share?

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09 Nov 2014 04:58 #26327 by john
Replied by john on topic Single-Board Universal Module
hello Guys

Chip RF switch, did it work ?

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09 Nov 2014 05:20 #26329 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
Still undetermined. I haven't been able to test mine out yet, I don't the test code PB is using. Haven't seen anything from PB in quite a while. Hope everything is okay with him.

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09 Nov 2014 16:12 #26331 by octagon
Replied by octagon on topic Single-Board Universal Module
It would appear that the board assembly is quite a challenge.
SeeedStudio offers, besides making low volume PCB at good prices, also prototype service. I have not tried their service as yet, I may, perhaps they are OK.
This may free up some time for PB to work on coding.

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21 Jan 2015 07:25 #27913 by john
Replied by john on topic Single-Board Universal Module
Hi Guys, any update information for this thread ?

i hope it will work . and hope Sadsack will come back :)

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21 Jan 2015 15:35 #27920 by mikemacwillie
Replied by mikemacwillie on topic Single-Board Universal Module
Not currently. PB seems to be taking a bit of a break. I've got a couple boards ready for firmware when he comes back.

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19 Feb 2015 01:47 - 20 Feb 2015 15:02 #28863 by Cereal_Killer
Replied by Cereal_Killer on topic Single-Board Universal Module
Hey guys, I'm new here, I'm an EE by trade and part of my daily work load is hot air reflow soldering of SMD components, specifically QFN packages and BGA's (I know a lot of the radio chips are QFN and I see mention of how hard these things are to build), I'd like to offer some help if it's needed.

I run a small business, not looking to sell ya'll anything but if / when you need a small batch of proto's assembled I'd be more than happy to do it for you. I can probably do around 10-15 of them a day and I'd be willing to spend a few days doing nothing but that (and of course I'd be happy to do smaller amounts, even just one or two at a time). Note because of the regulations and such I'm really not interested in selling these things, but I would be happy to solder up a batch for free if we could work something out.


Really looking forward to this, I hope I can contribute some labor sometime soon. Note I also specialize in PCB design and would be interested in making a drop-in 7E board as well...

Taranis X9E | DEVO 10 | Devo U7E | Taranis Q7

What I do in real life: rivergoequestrian.com/
Last edit: 20 Feb 2015 15:02 by Cereal_Killer. Reason: spellin' n such

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