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
SLOS743K –AUGUST 2011–REVISED APRIL 2014
www.ti.com
6.14.3.2.7 RX Wait Time Register (0x08)
The RX-wait-time timer is controlled by the value in the RX wait time register 0x08. This timer defines the
time after the end of the transmit operation in which the receive decoders are not active (held in reset
state). This prevents incorrect detections resulting from transients following the transmit operation. The
value of the RX wait time register defines this time in increments of 9.44 µs. This register is preset at
every write to ISO Control register 0x01 according to the minimum tag response time defined by each
standard.
Table 6-35. RX Wait Time Register (0x08)
Function: Defines the time after TX EOF when the RX input is disregarded for example, to block out electromagnetic disturbance
generated by the responding card.
Default: 0x1F at POR = H or EN = L and at each write toISO control register.
Bit Name Function Description
B7 Rxw7
Defines the time after the TX EOF during which the RX input is ignored. Time
B6 Rxw6
starts from the end of TX EOF.
B5 Rxw5
RX wait range is 9.44 µs to 2407 µs (1 to 255), Step size 9.44 µs.
B4 Rxw4
The following default timings are preset by the ISO Control register (0x01):
RX wait time
B3 Rxw3
9.44 µs → FeliCa
B2 Rxw2
66 µs → ISO14443A and B
B1 Rxw1
180 µs → Reserved
B1 Rxw0
293 µs → ISO15693 (TI Tag-It HF-I)
62 Detailed Description Copyright © 2011–2014, Texas Instruments Incorporated
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