Contactless communication device mode switching management
An embodiment device comprises a phase locked loop and a frequency locked loop having in common the same controlled oscillator. The device is firstly placed in the card emulation mode at the beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing within the contactless device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop, and upon reception by the contactless communication device of an indication sent by the reader indicating a further communication in a peer to peer mode with the reader, the device is secondly placed in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point depending on the reader carrier frequency and the frequency of the reference clock signal.
1. A method of managing operation of a contactless communication device, the contactless communication device configured to support a card emulation mode using active load modulation (ALM) and a peer to peer mode, and comprising a phase locked loop and a frequency locked loop having in common a same controlled oscillator, the method comprising:
firstly placing the contactless communication device in the card emulation mode at a beginning of a communication between the contactless communication device and a contactless reader, the firstly placing comprising synchronizing, within the contactless communication device, an ALM carrier frequency with a reader carrier frequency by operating at least the phase locked loop; and
upon reception by the contactless communication device of an indication sent by the contactless reader indicating a further communication in the peer to peer mode with the contactless reader, secondly placing the contactless communication device in the peer to peer mode, the secondly placing including deactivating the phase locked loop and operating the frequency locked loop with a reference clock signal and a frequency set point based on the reader carrier frequency and a frequency of the reference clock signal.
2. The method according to claim 1 , wherein the controlled oscillator is controlled for outputting an output oscillator signal having a frequency equal to the reader carrier frequency or to a multiple of the reader carrier frequency, and the frequency set point is a ratio between the frequency of the output oscillator signal and the frequency of the reference clock signal.
3. The method according to claim 1 , wherein the reference clock signal is provided by a reference clock generator, wherein the firstly placing comprises not operating the frequency locked loop and switching on the reference clock generator for it to be ready to deliver the reference clock signal to the frequency locked loop during the secondly placing.
4. The method according to claim 1 , wherein the synchronizing includes also operating the frequency locked loop with the reference clock signal.
5. The method according to claim 1 , further comprising storing the frequency set point in a memory.
6. A method of managing operation of a contactless communication device, the contactless communication device configured to support a card emulation mode using active load modulation (ALM) and a peer to peer mode, and comprising a phase locked loop and a frequency locked loop having in common a same controlled oscillator, the method comprising:
configuring the contactless communication device as a peer to peer reader, the configuring comprising, without using the phase locked loop, operating the frequency locked loop with a reference clock signal and a frequency set point based on a desired reader carrier frequency and a frequency of the reference clock signal.
7. The method according to claim 6 , wherein the controlled oscillator is controlled for outputting an output oscillator signal having a frequency equal to the desired reader carrier frequency or to a multiple of the desired reader carrier frequency, and the frequency set point is a ratio between the frequency of the output oscillator signal and the frequency of the reference clock signal.
8. The method according to claim 6 , further comprising storing the frequency set point in a memory.
9. A contactless communication device, configured to support a card emulation mode using active load modulation (ALM) and a peer to peer mode, the contactless communication device comprising:
a configurable module including a phase locked loop and a frequency locked loop having in common a same controlled oscillator, the configurable module having a first card emulation configuration in which the phase locked loop operates and the frequency locked loop operates with a reference clock signal, for synchronizing an ALM carrier frequency with a reader carrier frequency, and a first peer-to-peer configuration in which only the frequency locked loop operates with the reference clock signal and a frequency set point depending on the reader carrier frequency and a frequency of the reference clock signal; and
a controller configured for placing the configurable module in the first card emulation configuration at a beginning of a communication between the contactless communication device and a contactless reader, and for placing the configurable module in the first peer to peer configuration upon reception by the contactless communication device of an indication sent by the contactless reader indicating a further communication in the peer to peer mode with the contactless reader.
10. The contactless communication device according to claim 9 , wherein the controlled oscillator is configured to output an output oscillator signal having a frequency equal to the reader carrier frequency or to a multiple of the reader carrier frequency, and the frequency set point is a ratio between the frequency of the output oscillator signal and the frequency of the reference clock signal.
11. The contactless communication device according to claim 9 , further comprising a memory configured for storing the frequency set point.
12. The contactless communication device according to claim 9 , wherein the contactless communication device is a mobile phone.
13. A contactless communication device, configured to support a card emulation mode using active load modulation (ALM) and a peer to peer mode, the contactless communication device comprising:
a configurable module including a phase locked loop and a frequency locked loop having in common a same controlled oscillator, the configurable module having a second card emulation configuration in which only the phase locked loop operates for synchronizing an ALM carrier frequency with a reader carrier frequency, and a first peer-to-peer configuration in which only the frequency locked loop operates with a reference clock signal and a frequency set point depending on the reader carrier frequency and a frequency of the reference clock signal; and
a controller configured for placing the configurable module in the second card emulation configuration at a beginning of a communication between the contactless communication device and a contactless reader, and for placing the configurable module in the first peer-to-peer configuration upon reception by the contactless communication device of an indication sent by the contactless reader indicating a further communication in the peer to peer mode with the contactless reader.
14. The contactless communication device according to claim 13 , further comprising a reference clock generator configured, when switched on, to provide the reference clock signal, wherein the controller is configured, when the configurable module is placed in the second card emulation configuration, to switch on the reference clock generator for it to be ready to deliver the reference clock signal to the frequency locked loop when the configurable module switches in its first peer-to-peer configuration.
15. The contactless communication device according to claim 13 , wherein the controlled oscillator is configured to output an output oscillator signal having a frequency equal to the reader carrier frequency or to a multiple of the reader carrier frequency, and the frequency set point is a ratio between the frequency of the output oscillator signal and the frequency of the reference clock signal.
16. The contactless communication device according to claim 13 , further comprising a memory configured for storing the frequency set point.
17. The contactless communication device according to claim 13 , wherein the contactless communication device is a mobile phone.
18. A contactless communication device, configured to support a card emulation mode using active load modulation (ALM) and a peer to peer mode, the contactless communication device comprising:
a configurable module including a phase locked loop and a frequency locked loop having in common a same controlled oscillator, the configurable module having a second peer to peer configuration in which only the frequency locked loop operates with a reference clock signal and a frequency set point depending on a desired reader carrier frequency and a frequency of the reference clock signal; and
a controller configured for placing the configurable module in the second peer to peer configuration for making the contactless communication device acting as a peer to peer reader.
19. The contactless communication device according to claim 18 , wherein the controlled oscillator is configured to output an output oscillator signal having a frequency equal to the desired reader carrier frequency or to a multiple of the desired reader carrier frequency, and the frequency set point is a ratio between the frequency of the output oscillator signal and the frequency of the reference clock signal.
20. The contactless communication device according to claim 18 , further comprising a memory configured for storing the frequency set point.
21. The contactless communication device according to claim 18 , wherein the contactless communication device is a mobile phone.