SLOS757G December   2011  – March 2020 TRF7962A

PRODUCTION DATA.  

  1. 1Device Overview
    1. 1.1 Features
    2. 1.2 Applications
    3. 1.3 Description
    4. 1.4 Application Block Diagram
  2. 2Revision History
  3. 3Device Characteristics
    1. 3.1 Related Products
  4. 4Terminal Configuration and Functions
    1. 4.1 Pin Diagrams
    2. 4.2 Signal Descriptions
  5. 5Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Electrical Characteristics
    5. 5.5 Thermal Resistance Characteristics
    6. 5.6 Switching Characteristics
  6. 6Detailed Description
    1. 6.1  Functional Block Diagram
    2. 6.2  Power Supplies
    3. 6.3  Supply Arrangements
    4. 6.4  Supply Regulator Settings
    5. 6.5  Power Modes
    6. 6.6  Receiver – Analog Section
      1. 6.6.1 Main and Auxiliary Receiver
      2. 6.6.2 Receiver Gain and Filter Stages
    7. 6.7  Receiver – Digital Section
      1. 6.7.1 Received Signal Strength Indicator (RSSI)
        1. 6.7.1.1 Internal RSSI – Main and Auxiliary Receivers
        2. 6.7.1.2 External RSSI
    8. 6.8  Oscillator Section
    9. 6.9  Transmitter - Analog Section
    10. 6.10 Transmitter - Digital Section
    11. 6.11 Transmitter – External Power Amplifier or Subcarrier Detector
    12. 6.12 Communication Interface
      1. 6.12.1 General Introduction
      2. 6.12.2 FIFO Operation
      3. 6.12.3 Parallel Interface Mode
      4. 6.12.4 Reception of Air Interface Data
      5. 6.12.5 Data Transmission to MCU
      6. 6.12.6 Serial Interface Communication (SPI)
        1. 6.12.6.1 Serial Interface Mode Without Slave Select (SS)
        2. 6.12.6.2 Serial Interface Mode With Slave Select (SS)
      7. 6.12.7 Direct Mode
    13. 6.13 Direct Commands from MCU to Reader
      1. 6.13.1  Command Codes
      2. 6.13.2  Reset FIFO (0x0F)
      3. 6.13.3  Transmission With CRC (0x11)
      4. 6.13.4  Transmission Without CRC (0x10)
      5. 6.13.5  Transmit Next Time Slot (0x14)
      6. 6.13.6  Block Receiver (0x16)
      7. 6.13.7  Enable Receiver (0x17)
      8. 6.13.8  Test Internal RF (RSSI at RX Input With TX On) (0x18)
      9. 6.13.9  Test External RF (RSSI at RX Input With TX Off) (0x19)
      10. 6.13.10 Register Preset
    14. 6.14 Register Description
      1. 6.14.1 Register Overview
        1. 6.14.1.1 Main Configuration Registers
          1. 6.14.1.1.1 Chip Status Control Register (0x00)
          2. 6.14.1.1.2 ISO Control Register (0x01)
        2. 6.14.1.2 Protocol Subsetting Registers
          1. 6.14.1.2.1 TX Pulse Length Control Register (0x06)
          2. 6.14.1.2.2 RX No Response Wait Time Register (0x07)
          3. 6.14.1.2.3 RX Wait Time Register (0x08)
          4. 6.14.1.2.4 Modulator and SYS_CLK Control Register (0x09)
          5. 6.14.1.2.5 RX Special Setting Register (0x0A)
          6. 6.14.1.2.6 Regulator and I/O Control Register (0x0B)
        3. 6.14.1.3 Status Registers
          1. 6.14.1.3.1 IRQ Status Register (0x0C)
          2. 6.14.1.3.2 Collision Position and Interrupt Mask Registers (0x0D and 0x0E)
          3. 6.14.1.3.3 RSSI Levels and Oscillator Status Register (0x0F)
        4. 6.14.1.4 Test Registers
          1. 6.14.1.4.1 Test Register (0x1A)
          2. 6.14.1.4.2 Test Register (0x1B)
        5. 6.14.1.5 FIFO Control Registers
          1. 6.14.1.5.1 FIFO Status Register (0x1C)
          2. 6.14.1.5.2 TX Length Byte1 Register (0x1D) and TX Length Byte2 Register (0x1E)
  7. 7Applications, Implementation, and Layout
    1. 7.1 TRF7962A Reader System Using SPI With SS Mode
      1. 7.1.1 General Application Considerations
      2. 7.1.2 Schematic
    2. 7.2 System Design
      1. 7.2.1 Layout Considerations
      2. 7.2.2 Impedance Matching TX_Out (Pin 5) to 50 Ω
      3. 7.2.3 Reader Antenna Design Guidelines
  8. 8Device and Documentation Support
    1. 8.1 Getting Started and Next Steps
    2. 8.2 Device Nomenclature
    3. 8.3 Tools and Software
    4. 8.4 Documentation Support
    5. 8.5 Support Resources
    6. 8.6 Trademarks
    7. 8.7 Electrostatic Discharge Caution
    8. 8.8 Export Control Notice
    9. 8.9 Glossary
  9. 9Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.12.2 FIFO Operation

The FIFO is a 12-byte register at address 0x1F with byte storage locations 0 to 11. FIFO data is loaded in a cyclical manner and can be cleared by a reset command (0x0F, see Figure 6-9 showing this Direct Command).

Associated with the FIFO are two counters and three FIFO status flags. The first counter is a 4-bit FIFO byte counter (bits B0 to B3 in register 0x1C) that keeps track of the number of bytes loaded into the FIFO. If the number of bytes in the FIFO is n, the register value is n – 1 (number of bytes in FIFO register). If 8 bytes are in the FIFO, the FIFO counter (bits B0 to B3 in register 0x1C) has the value 7.

A second counter (12 bits wide) indicates the number of bytes being transmitted (registers 0x1D and 0x1E) in a data frame. An extension to the transmission-byte counter is a 4-bit broken-byte counter also provided in register 0x1E (bits B0 to B3). Together these counters make up the TX length value that determines when the reader generates the EOF byte.

FIFO status flags are as follows:

  1. FIFO overflow (bit B4 of register 0x1C): Indicates that the FIFO was loaded too soon
  2. FIFO level too low (bit B5 of register 0x1C): Indicates that only three bytes are left to be transmitted (Can be used during transmission.)
  3. FIFO level high (bit B6 of register 0x1C): Indicates that nine bytes are already loaded into the FIFO (Can be used during reception to generate a FIFO reception IRQ. This is to notify the MCU to service the reader in time to ensure a continuous data stream.)

During transmission, the FIFO is checked for an almost-empty condition, and during reception for an almost-full condition. The maximum number of bytes that can be loaded into the FIFO in a single sequence is 12 bytes.

NOTE

The number of bytes in a frame, transmitted or received, can be greater than 12 bytes.

During transmission, the MCU loads the TRF7962A FIFO (or, during reception, the MCU removes data from the FIFO), and the FIFO counter counts the number of bytes being loaded into the FIFO. Meanwhile, the byte counter keeps track of the number of bytes being transmitted. An interrupt request is generated if the number of bytes in the FIFO is less than 3 or greater than 9, so that MCU can send new data or remove the data as necessary. The MCU also checks the number of data bytes to be sent, so as to not surpass the value defined in TX length bytes. The MCU also signals the transmit logic when the last byte of data is sent or was removed from the FIFO during reception. Transmission starts automatically after the first byte is written into FIFO.

TRF7962A check_fifo_status_register_slos732.pngFigure 6-10 Checking the FIFO Status Register (Using SPI With SS Mode)