How Improving anticollison of Reader Lib function DiscoveryLoop?

[oliviergiard]

Hello,

I'm working on a system using CLRC663 for ISO15693 tag detection. My application need to work with multi-tag (max 10 if possible, higher would be great). I use the last version of the NFC Reader Library (v05.12.00) and the DiscoveryLoop function to get tag informations. I'm in front of many collision problems. Does any one has solutions to improve the anticollision algorithm or parameter setttings using NFC reader Lib and CLRC663?

Thanks in advance

Olivier

[oliviergiard]

Hi Kan,

I got the solution to my problem.

I used last tag ICODE SLIX2 generation, but this is not the most important. The key is to have an ICODE SLIX tag with "stayquiet" capability AVAILABLE!!

I start my code with a discovery loop to find at least one tag. The next polling, I start to put the known tag in quiet mode, then I run a new discovery loop, and so on.

At each polling I monitor if tag is added or removes.

Now I can track more than 10 tags in my system!

Thanks for support.

Kind regards.

Olivier

[oliviergiard]

Hi Kan,

Thanks for the doc.

I did different experimentation:

1) I did work also inside the discoveryloop code, trying to put tag in quiet or quiet persistent during the collision resolution, but i did have no success.

2) After the discovery loop collision resolution process, I put all tags in quiet, but without keep the RF field on. I try a second discovery loop, put all tag set in quiet does reply to the inventory... I suspect that a flag is requiered to really keep tag in quiet mode, but I don't find....

Any information a precise description of the quiet behavior are welcome.

Kind regards.

Olivier

[oliviergiard]

Hi Kan,

The "NfcrdlibEx5_ISO15693" run a discovery loop in a while until a card is detected. I think it is well adapted for use case of system having 100% on the reader and only one card is use.

I did hack the TX and RX of the CLRC663 during discovery loop. I'll try to work on the amplitude modulation index to fine tune my antenna as explain in the application note AN11019.

If you have any clue from your side, please let me informed.

Many thanks

Kind regards.

Olivier

[Kan_Li]

Hi Olivier,

The NFC reader library can support multiple tags, please kindly refer to Activating multiple Tags using NFC Reader Library  for details.

Hope that helps,

Have a great day,
Kan

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[oliviergiard]

Hello Kan,

I did analyse the behavior of the function "phacDiscLoop_Sw_Int_PollMode" and "phacDiscLoop_Sw_Int_ColsnReslnActivity" on my oscilloscope (with config CLRC663/SIGOUT=RX) with different tag position. I have 3 situations depending on the position of tags

1) with 3 tags, the first inventory of the discovery loop (tech detection made with one slot) does not see any signal send back by the tag. I think that the collision is too important for the RX to detect anything. I did not test to change the RX detector sensitivity, the default is used.

2) with 5 tags, when I loop multiple time on the complete discovery loop  process, sometimes I see 4 tags, sometimes 5 tags. But no collision detected on function "phacDiscLoop_Sw_Int_CollisionResolutionV". On the scope I clearly see on one slot a tag appear and at next loop the tag is not answering (or not detected because I monitor the SIGOUT:RX)

3) with 5 tags, but changing the position of the tag, I can see sometimes a collision.

My goal is to have reliability on my application and be sure to detect all tag.

I see that the persistent quiet function can put tag in quiet mode for a certain time even if the filed is witch off for a lower time than the persistent time. Maybe i can place this function inside the  "phacDiscLoop_Sw_Int_CollisionResolutionV" loop. What do you thinks? What is the code to add?

Thanks in advance.

Kind regards.

Olivier

[Kan_Li]

Hi Olivier,

Have you tried the demo of "NfcrdlibEx5_ISO15693"? Does it make any difference?

Have a great day,
Kan

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[Kan_Li]

Hi Olivier,

Would you please specify which collision problem you have using CLRC663 for ISO15693 tag based on NFC Reader Library (v05.12.00)? I may try to reproduce the issue here. Thanks for your patience!

Have a great day,
Kan

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