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LINUX-NFC-TRF7970A: TRF7970 RSSI detection loop

MK
Intellectual 980 points
Part Number: LINUX-NFC-TRF7970A
Other Parts Discussed in Thread: TRF7970A

Hi Team,

My customer is detecting the presence of passive cards with the TRF7970A without the need for additional hardware. They are using the Linux NFC Subsystem with the provided NFC trf7970a.c drive and a boostpack DLP-7970AB.

According to https://www.ti.com/lit/an/sloa184/sloa184.pdf , an RSSI detection loop is the only solution that does not require extra hardware. Is this is different from the example polling loop in the reader/writer example on page 14(link)? Or is the RSSI detection implemented in the “Response Received?” block?

The goal is to have the reader in a proximity detection loop, consuming as little power as possible, until a tag is presented and begin sending commands to read from it. I’m trying to determine how this RSSI detection loop will save power compared to normal polling. Is polling the same as the RSSI detection loop?

Looking forward to the discussion!

Best Regards,

Madhurya

  • 0
    TI__Mastermind 18265 points

    Hi Madhurya,

    I checked both resources you referred to and I can see no difference. Because after the "Response Received" block the anticollision loop follows this block must work also as RSSI detection loop. In both cases the TRF7970A has to send a full TX protocol which is the power consuming part. A power saving would require external hardware to keep the TX time as short as possible.

    Best Regards,

    Helfried

  • 0 in reply to Helfried Vollbrecht
    TI__Mastermind 18265 points

    Hi Madhurya.

    I haven’t heard back from you for a while, so this tread is being closed. If you wish to continue the discussion, please post a reply with an update below (or create a new thread).

    Best regards,
    Helfried