NFC DEVICE DETECTION

1 . A method, comprising:

operating a near-field communication circuit of a first NFC device to alternate, in low power mode, between: first phases of emission of field bursts and second phases spanning an entire duration separating two successive first phases;

wherein each second phase comprises a third phase of enabling a field detector, wherein said third phase either:

a) extends for an entire duration of the second phase; or

b) has a duration interrupted by one or more fourth phases of disabling the field detector, wherein each fourth phase has a duration shorter than a minimum duration of each first phase.

2 . The method according to claim 1 , wherein the duration of each fourth phase of disabling the field detector is at least ten times shorter than the minimum duration of each first phase.

3 . The method according to claim 1 , wherein the duration of each fourth phase of disabling the field detector is at least fifty times shorter than the minimum duration of each first phase.

4 . The method according to claim 1 , further comprising switching the first NFC device to an operating mode of transmission of a polling sequence when a second NFC device is detected within range.

5 . The method according to claim 4 , wherein transmission of the polling sequence is made in accordance with an NFC Forum specification.

6 . The method according to claim 1 , further comprising detecting a second NFC device by the field detector of the first NFC device during one of the second phases.

7 . The method according to claim 6 , wherein detecting the second NFC device comprises detecting an emission, by the second NFC device, of at least one field burst.

8 . The method according to claim 7 , further comprising confirming presence of the second NFC device within range by estimating, using the near-field communication circuit of the first NFC device, an oscillation frequency of said at least one field burst emitted by the second NFC device.

9 . The method according to claim 8 , wherein each field burst emitted by the second NFC device has a duration equal to approximately 60 μs.

10 . The method according to claim 6 , wherein detecting the second NFC device comprises detecting an emission, by the second NFC device, of a single field burst.

11 . The method according to claim 6 , wherein detecting the second NFC device comprises detecting an emission, by the second NFC device, of successive first and second field bursts.

12 . The method according to claim 11 , further comprising confirming presence of the second NFC device within range by estimating a duration separating the successive first and second field bursts.

13 . The method according to claim 12 , wherein estimating the duration separating the first and second field bursts comprises counting by the first NFC device a time between the successive first and second field bursts.

14 . The method according to claim 11 , further comprising confirming presence of the second NFC device within range by estimating of a duration of the second field burst.

15 . The method according to claim 1 , further comprising:

switching the first NFC device to an operating mode of transmission of a polling sequence when a second NFC device is detected within range; and

configuring the first and second NFC devices to communicate in peer-to-peer mode.

16 . A computer program product, comprising a non-transient storage support comprising instructions configured when executed by a processor to implement the method according to claim 1 .

17 . An electronic device comprising the computer program product according to claim 16 .

18 . An electronic circuit, configured to implement the method according to claim 1 .

19 . An electronic device comprising the electronic circuit according to claim 18 .