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
6.14.3.2.10 Regulator and I/O Control Register (0x0B)
Table 6-38. Regulator and I/O Control Register (0x0B)
Function: Control the three voltage regulators
Default: 0x87 at POR = H or EN = L
Bit Name Function Description
0 = Manual settings; see B0
to B2 in Table 6-39 and Auto system sets V
DD_RF
= V
IN
– 250 mV and V
DD_A
= V
IN
– 250 mV and
B7 auto_reg
Table 6-40 V
DD_X
= V
IN
– 250 mV, but not higher than 3.4 V.
1 = Automatic setting
Internal peak detectors are disabled, receiver inputs (RX_IN1 and RX_IN2)
Support for external power
B6 en_ext_pa accept externally demodulated subcarrier. At the same time ASK/OOK pin 12
amplifier
becomes modulation output for external TX amplifier.
When B5 = 1, maintains the output driving capabilities of the I/O pins connected
1 = enable low peripheral
B5 io_low to the level shifter under low voltage operation. Should be set 1 when V
DD_I/O
communication voltage
voltage is between 1.8 V to 2.7 V.
B4 Unused No function Default is 0.
B3 Unused No function Default is 0.
B2 vrs2
Voltage set MSB voltage Vrs3_5 = L: V
DD_RF
, V
DD_A
, V
DD_X
range 2.7 V to 3.4 V; see Table 6-39 and
B1 vrs1
set LSB Table 6-40
B0 vrs0
Table 6-39. Supply-Regulator Setting – Manual 5-V System
Option Bits Setting in Control Register
Register Action
B7 B6 B5 B4 B3 B2 B1 B0
00 1 5-V system
0B 0 Manual regulator setting
0B 0 1 1 1 V
DD_RF
= 5 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 1 1 0 V
DD_RF
= 4.9 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 1 0 1 V
DD_RF
= 4.8 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 1 0 0 V
DD_RF
= 4.7 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 0 1 1 V
DD_RF
= 4.6 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 0 1 0 V
DD_RF
= 4.5 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 0 0 1 V
DD_RF
= 4.4 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
0B 0 0 0 0 V
DD_RF
= 4.3 V, V
DD_A
= 3.4 V, V
DD_X
= 3.4 V
Table 6-40. Supply-Regulator Setting – Manual 3-V System
Option Bits Setting in Control Register
Register Action
B7 B6 B5 B4 B3 B2 B1 B0
00 0 3-V system
0B 0 Manual regulator setting
0B 0 1 1 1 V
DD_RF
= 3.4 V, V
DD_A
and V
DD_X
= 3.4 V
0B 0 1 1 0 V
DD_RF
= 3.3 V, V
DD_A
and V
DD_X
= 3.3 V
0B 0 1 0 1 V
DD_RF
= 3.2 V, V
DD_A
and V
DD_X
= 3.2 V
0B 0 1 0 0 V
DD_RF
= 3.1 V, V
DD_A
and V
DD_X
= 3.1 V
0B 0 0 1 1 V
DD_RF
= 3.0 V, V
DD_A
and V
DD_X
= 3.0 V
0B 0 0 1 0 V
DD_RF
= 2.9 V, V
DD_A
and V
DD_X
= 2.9 V
0B 0 0 0 1 V
DD_RF
= 2.8 V, V
DD_A
and V
DD_X
= 2.8 V
0B 0 0 0 0 V
DD_RF
= 2.7 V, V
DD_A
and V
DD_X
= 2.7 V
Copyright © 2011–2014, Texas Instruments Incorporated Detailed Description 65
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