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Does TMS3705 support FDX, or only HDX?

Malger Ralger
Prodigy 30 points
Other Parts Discussed in Thread: TMS3705

Hi,

I have a HomeAgain (http://microchip.homeagain.com/) transponder which is claimed to operate at 134.2 kHz according to ISO specs (I imagine they mean ISO 11784 & 11785). I also have the TMS3705 hooked up with an antenna outputting 134.45 kHz, >50V at the capacitor/coil junction.

When reading the SCIO pin the IC sends the 0xAF byte indicating that the antenna is working. Finally, following the 0xAF byte, the IC sends a 19 byte data series (after extracting each byte from the start, and end 1 and 0, respectively, flipping each byte, and inverting them).

The problem is that it sends this data (I didn't check whether it was consistent) whether my transponder is present or not. So I have to assume it just garbage. Still I'm curious why 19 bytes. Anyway, I read somewhere that this transponder uses FDX-B, so the first question is whether TMS3705 supports FDX?

Assuming it is FDX, I should see the transponder response while the IC is charging it. But, again, whether the transponder is present, there are 50+mv variations in the amplitude of the coil voltage, so maybe that's where the IC gets the 19 bytes. I tested also with a large ID card which is a 125 kHz transponder, but I could see no changes between the transponder being present or absent. For both transponders I also watched for changes above noise after the IC stops the antenna, in case it's HDX, but nothing.

So my question is about the FDX support. But also, is noise this large expected in the coil?

P.S. When I looked at the fft of the coil wave, there as a giant spike at 134 kHz, but also two large side lobes at ~120 kHz and ~160kHz range. There were also smaller, but regular spikes at every tens of kHz or so.

Thanks!

  • 0
    TI__Guru* 91206 points

    Matt - 

    the TMS3705 only supports TI LF HDX technology, as FDX is inferior implementation of ISO11784/785. 

    Here are some additional notes on what you should see with the device and some technical reasons why you should never use FDX

    0486.Notes on TMS3705A1DRG4 Read.ppt

    8737.FDX VS HDX.PDF

     

  • 0 in reply to Josh Wyatt
    Prodigy 30 points

    Thanks for the reply; you should add the slides to the TMS3705 doc page.

    I do agree that HDX seems superior to FDX, however, the transponder is for my cat. I did find  the TRPGR30TGC transponder which seems small enough to be implanted, but I'm wondering whether a common scanner owned by a vet will be able to read the HDX protocol, in case it gets lost. Or should a scanner which implements ISO11784/785 support both FDX/HDX?

    The other question is about the uniqueness of the transponder ID. Will it clash with an ID of a transponder by e.g. HomeAgain chip? They claim that they accept in their databases IDs from other manufacturers (http://public.homeagain.com/faq.html#needmicrochip) so maybe this is not an issue?

    I suppose the best way is to simply take the transponder to a vet and see if they can read it.

    Thanks,

    Matt

  • 0 in reply to Malger Ralger
    TI__Guru* 91206 points

    Matt - 

    first, you must understand that the ISO11784/785 and later update of these with ISO14223 is mainly for the ID/tracking of animals which are to be consumed (i.e. cows, pigs, sheep, and later fish) to quickly identify when there is an outbreak of some disease where the origin and every place the animal has been needs to be known so as to minimize the impact on people and to stop the spread of whatever the contagion might be. Some studies/simulations were done years ago which showed that by using a system like this works effectively in the containment process. This is why countries like Australia, New Zealand and others have made it law to have these types of animals tagged (usually with ear tags or bolus, as you really don't want glass transponders involved in the butchering process). There is a well defined numbering structure (which includes a country code) for this which is governed by an international organization and requires registration. The extension of using this technology in pets/companion animals makes sense, but the numbering structure does not necessarily extend here and to be honest, since HDX and HDX+ outperforms FDX and FDX-B every day of the week, and we did not make a 12mm tag until recently, our competitors identified companion animals as a growth market for themselves and pursued it. The size of the tag here played a big part in that, as the next smallest transponder we made available is 23mm x 3mm, which did not lend itself to being implanted in the smaller animals like cats and miniature/toy versions of dogs.

    So - most likely the vets scanner might only read FDX or FDX-B, but now that we have created the 12mm x 2mm device, i would imagine that moving forward you will see dual readers being created for the pet vet market, like what is available already in the other animals tracking market.

    As far as controlling the uniqueness of the serial #, we take great care in making sure we do not issue any duplicates...i cannot comment on other mfgs control processes.         

  • 0 in reply to Josh Wyatt
    Prodigy 140 points

    Is there a single chip , or chip combo that can be used to read hdx and fdx-b tags?

  • 0 in reply to Christo Wiese
    TI__Guru* 91206 points
    we do not support FDX tags, only HDX.