SLOA208B November   2014  – March 2019 TRF7970A , TRF7970A

 

  1.   NFC card emulation using the TRF7970A
    1.     Trademarks
    2.     Terms, Definitions, and Symbols
    3. 1  Introduction
    4. 2  Card Emulation
      1. 2.1 Anticollision
        1. 2.1.1 Card Emulation Type A
        2. 2.1.2 Card Emulation Type B
      2. 2.2 Data Exchange
    5. 3  Configuration and Commands for Type 4 Tag Platforms
      1. 3.1 Overview of Type 4 Tag Configuration
        1. 3.1.1 Tag
        2. 3.1.2 Applications
        3. 3.1.3 Files
      2. 3.2 Firmware Structure
        1.       Example 1. Type 4 Tag Structures Within Example Firmware
        2. 3.2.1 tType4AppDS
        3. 3.2.2 tType4App
        4. 3.2.3 tType4File
        5. 3.2.4 Example Setup
          1.        Example 2. Example Setup of a Type 4 Tag Structure
      3. 3.3 File Structure
        1. 3.3.1 Capability Container
          1.        Example 3. Format of the Capability Container for a Tag With Two Files
        2. 3.3.2 Text RTD
          1.        Example 4. Example of a Text RTD Within an NDEF File
        3. 3.3.3 URI RTD
          1.        Example 5. Example of a URI RTD Within a Proprietary File
        4. 3.3.4 Smart Poster
        5. 3.3.5 V-Card
        6. 3.3.6 MIME
      4. 3.4 Available Type 4 Tag Commands
        1. 3.4.1 Frame Format
        2. 3.4.2 Select
        3. 3.4.3 Read Binary
        4. 3.4.4 Update Binary
      5. 3.5 Modifying Stored Tag Information
    6. 4  Hardware Description
      1. 4.1 LaunchPad™ Development Kit and BoosterPack™ Plug-in Module Setup
        1. 4.1.1 BoosterPack Plug-in Module: DLP-7970ABP
        2. 4.1.2 LaunchPad Development Kit: MSP-EXP430F5529LP
        3. 4.1.3 LaunchPad Development Kit: MSP-EXP432P401R
      2. 4.2 Bundle Available for Purchase
    7. 5  Card Emulation Firmware Example
      1. 5.1 Card Emulation APIs
      2. 5.2 Implementing a Card Emulation Sample Application
        1. 5.2.1 Low-Level Initialization
          1.        Example 6. MCU and TRF7970A Initialization Code Snippet
        2. 5.2.2 Card Emulation NFC Stack Setup
          1.        Example 7. Card Emulation Initialization Code
        3. 5.2.3 Emulation of Different RTDs
    8. 6  Quick Start Guide
    9. 7  Operational Overview
    10. 8  Card Emulation Interoperability Results
    11. 9  Conclusion
    12. 10 References
  2.   Revision History

7 Operational Overview

The card emulation example on the MSP430F5529 supports the emulation of Type 4A and Type 4B tag platforms. When emulating a tag, the TRF7970A transceiver is a listening device. It waits for a RF field to be presented and for the correct over-the-air commands to be transmitted. If additional NFC modes are enabled that allow the TRF7970A to act as a polling device, then the transceiver needs to toggle between polling and listening states (see Figure 15).

A function is used to run the NFC stack that handles all states of communication from technology detection to the data exchange protocol. When the NFC stack function is called it evaluates the enabled modes and calls the appropriate state machines. For card emulation, the NFC stack uses the target state machine, enters a listening mode, and then the firmware waits for a technology to be activated for 500 ms. If no technology is activated during that time, the NFC stack returns back to the main code. Note that this behavior would differ if a polling mode was enabled. In that case, the NFC stack would either switch to a polling mode instead before returning to the main code, or start by polling and then listen for the 500 ms. The interval of 500 ms is used to provide a fluid user experience and can be increased or decreased as needed on an application basis.

fig21_switching_mechanism.pngFigure 15. NFC Initiator and Target Switching Mechanism

The second mode requires a host (PC) to run the Embedded RF Tool GUI and connect to the MSP430F5529 LaunchPad development kit through the USB CDC (Figure 16 shows the system block diagram). The GUI lets the user select the card emulation modes to enable or disable.

fig22_demo_block_dgm.gifFigure 16. Card Emulation Demo System Block Diagram