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12.3.3.1 General target mode configuration (GTM)
Depending on the configuration a certain protocol can be selected/disabled for the card
mode detection:
• Miller decoder is enabled > TypeA/NFC 106kbps is detected
• NRZ decoder is enabled > TypeB 106kbps is detected
• Manchester decoder is enabled > Felica / NFC 212/424kbps is detected
It is not possible to enable only one baudrate for the Felica protocol.
12.3.3.2 Card mode detection - CMA active
Usually, in the card mode the CMA is enabled to handle the Type A activation
automatically. In case a Type A command is detected, the CMA takes over the activation
process including the transceive flow control. In such a case after the initial
MODE_DETECTED_IRQ all subsequent IRQs are disabled until either the Type A
activation is complete (indicated by an CARD_ACTIVATED_IRQ) or a different protocol
is detected. For the later scenario, the MODE_DETECTED_IRQ is set and all IRQs are
unmasked again.
12.3.3.3 Card mode detection - FW handling
In case a protocol different to Type A (Type B or Felica) is detected FW needs to handle
the complete activation process. In such a case CMA is inactive and all IRQs are passed
to FW.
12.3.4 Active Load Modulation
When PN7462 family is used in the card emulation mode, or P2P passive target mode, it
has to modulate the field emitted by the external reader or NFC passive initiator.
To modulate the field, PN7462 family has two possibilities:
• Passive Load Modulation (PLM): the reader modifies its antenna characteristics,
• Active Load Modulation (ALM): the reader generates a small field, in phase
The modulation type to use, depends on the external reader and PN7462 family antenna,
and must be chosen depending on the application.
12.3.5 Low Power Card Detection
If a card is moved into the RF field of the reader, then in many cases the antenna is
detuned and the voltage value at the reader changes. This fact is exploited for low power
card detection, where the AGC is used to detect small changes of the RF field. The AGC
is used in fast-mode in order to keep the operational time to a minimum.
The following steps are performed in a loop:
1. Write the Rx-Divider nominal value into the
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which will be detecting by the reader through the antenna coupling.
opposition with the reader's emitted field, which will be detected by the reader
reception stage.
CLIF_AGC_VALUE_REG.AGC_VALUE_RM
All information provided in this document is subject to legal disclaimers.
Rev. 1.4 — 14 May 2018
314514
UM10858
PN7462 family HW user manual
© NXP B.V. 2018. All rights reserved.
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