User's Manual
Table Of Contents
- 1 Device Overview
- Table of Contents
- 2 Revision History
- 3 Device Characteristics
- 4 Terminal Configuration and Functions
- 5 Specifications
- 6 Detailed Description
- 6.1 Overview
- 6.2 System Block Diagram
- 6.3 Power Supplies
- 6.4 Receiver – Analog Section
- 6.5 Receiver – Digital Section
- 6.6 Oscillator Section
- 6.7 Transmitter – Analog Section
- 6.8 Transmitter – Digital Section
- 6.9 Transmitter – External Power Amplifier and Subcarrier Detector
- 6.10 TRF7970A IC Communication Interface
- 6.11 Special Direct Mode for Improved MIFARE Compatibility
- 6.12 NFC Modes
- 6.13 Direct Commands from MCU to Reader
- 6.13.1 Command Codes
- 6.13.1.1 Idle (0x00)
- 6.13.1.2 Software Initialization (0x03)
- 6.13.1.3 Initial RF Collision Avoidance (0x04)
- 6.13.1.4 Response RF Collision Avoidance (0x05)
- 6.13.1.5 Response RF Collision Avoidance (0x06, n = 0)
- 6.13.1.6 Reset (0x0F)
- 6.13.1.7 Transmission With CRC (0x11)
- 6.13.1.8 Transmission Without CRC (0x10)
- 6.13.1.9 Delayed Transmission With CRC (0x13)
- 6.13.1.10 Delayed Transmission Without CRC (0x12)
- 6.13.1.11 Transmit Next Time Slot (0x14)
- 6.13.1.12 Block Receiver (0x16)
- 6.13.1.13 Enable Receiver (0x17)
- 6.13.1.14 Test Internal RF (RSSI at RX Input With TX ON) (0x18)
- 6.13.1.15 Test External RF (RSSI at RX Input with TX OFF) (0x19)
- 6.13.1.16 Receiver Gain Adjust (0x1A)
- 6.13.1 Command Codes
- 6.14 Register Description
- 7 Application Schematic and Layout Considerations
- 8 Device and Documentation Support
- 9 Mechanical Packaging and Orderable Information
TRF7970A
www.ti.com
SLOS743K –AUGUST 2011–REVISED APRIL 2014
6.14.3.3.5 Special Functions Register (0x11)
Table 6-49. Special Functions Register (0x11)
Function: Indicate IRQ status for RX operations.
Bit Name Function Description
B7 Reserved Reserved
B6 Reserved Reserved
B5 Reserved Reserved
B4 Reserved Reserved
B3 Reserved Reserved
B2 Reserved Reserved
B1 Reserved Reserved
Copy of the RX start signal
Signals the RX SOF was received and the RX is in progress. IRQ when RX is
B0 irg_srx (Bit 6) of the IRQ Status
completed.
Register (0x0C)
6.14.3.3.6 Adjustable FIFO IRQ Levels Register (0x14)
Table 6-50. Adjustable FIFO IRQ Levels Register (0x14)
Function: Adjusts level at which FIFO indicates status by IRQ
Default: 0x00 at POR = H and EN = L
Bit Name Function Description
B7 Reserved Reserved
B6 Reserved Reserved
B5 Reserved Reserved
B4 Reserved Reserved
B3 Wlh_1 Wlh_1 Wlh_0 IRQ Level
0 0 124
FIFO high IRQ level (during
0 1 120
RX)
B2 Wlh_0
1 0 112
1 1 96
B1 Wll_1 Wll_1 Wll_0 IRQ Level
0 0 4
FIFO low IRQ level (during
0 1 8
TX)
B0 Wll_0
1 0 16
1 1 32
6.14.3.3.7 NFC Low Field Level Register (0x16)
Table 6-51. NFC Low Field Level Register (0x16)
Function: Defines level for RF collision avoidance
Default: 0x00 at POR = H and EN = L.
Bit Name Function Description
B7 Clex_dis Disable clock extractor NFC passive 106-kbps and ISO14443A card emulation
B6 Hash6 N/A
B5 Hash5 N/A
B4 Hash4 N/A
B3 Hash3 N/A
B2 Rfdet_I2
RF field level for RF Comparator output is displayed in B6 of the NFC Target Protocol register
B1 Rfdet_I1
collision avoidance (0x19)
B0 Rfdet_I0
Copyright © 2011–2014, Texas Instruments Incorporated Detailed Description 69
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