SPRAC94D September   2018  – March 2022 AFE030 , AFE031 , TMS320F28075 , TMS320F28075-Q1 , TMS320F28076 , TMS320F28374D , TMS320F28374S , TMS320F28375D , TMS320F28375S , TMS320F28375S-Q1 , TMS320F28376D , TMS320F28376S , TMS320F28377D , TMS320F28377D-EP , TMS320F28377D-Q1 , TMS320F28377S , TMS320F28377S-Q1 , TMS320F28379D , TMS320F28379D-Q1 , TMS320F28379S

 

  1.   Trademarks
  2. 1 FSK Overview
  3. 2 Hardware Overview
    1. 2.1 Block Diagram
    2. 2.2 Hardware Setup
  4. 3 Interfacing With the AFE03x
    1. 3.1 Configuring the AFE031
  5. 4 Transmit Path
    1. 4.1 FSK Example Specifications
    2. 4.2 PWM Mode
      1. 4.2.1 Software Implementation
      2. 4.2.2 Testing Results
      3. 4.2.3 HRPWM vs. EPWM
    3. 4.3 DAC Mode
      1. 4.3.1 Software Implementation
      2. 4.3.2 Testing Results
      3. 4.3.3 OFDM Ability
    4. 4.4 Porting TX to LAUNCHXL-F280049C
      1. 4.4.1 PWM Mode Specific Porting
      2. 4.4.2 DAC Mode Specific Porting
  6. 5 Receive Path
    1. 5.1 Receive Path Overview
    2. 5.2 Receiver Software Implementation
      1. 5.2.1 Initial Setup and Parameters
      2. 5.2.2 Interrupt Service Routines
      3. 5.2.3 Run Time Operation
      4. 5.2.4 Testing Results
      5. 5.2.5 System Utilization
      6. 5.2.6 Device Dependency and Porting
    3. 5.3 Tuning and Calibration
      1. 5.3.1 Setting the AFE03X's PGAs
      2. 5.3.2 Automatic Gain Control (AGC)
      3. 5.3.3 Setting the Bit Detection Threshold
      4. 5.3.4 FSK Correlation Detector Library
    4. 5.4 Porting RX to LAUNCHXL-F280049C
  7. 6 Interfacing With a Power Line
    1. 6.1 Line Coupling
    2. 6.2 Coupling to an AC Line
      1. 6.2.1 Low Voltage Capacitor
      2. 6.2.2 The Ratio of the Transformer
      3. 6.2.3 HV Capacitor
      4. 6.2.4 HV Side Inductor
    3. 6.3 Coupling to DC Line
    4. 6.4 Protection Circuit
      1. 6.4.1 Metal Oxide Varistors
      2. 6.4.2 Transient Voltage Suppressors
      3. 6.4.3 Current Steering Diodes
    5. 6.5 Determining PA Power Supply Requirements
  8. 7 Summary
  9. 8 References
  10. 9 Schematics
    1. 9.1 Schematics (PWM Mode)
    2. 9.2 Schematics (DAC Mode)
  11. 10Revision History

3 Interfacing With the AFE03x

When interfacing with the AFE03x as a transmitter, first decide which mode of operation to use for the AFE03x, DAC mode or PWM mode.

In DAC mode, the C2000 sends SPI data to update an internal DAC on the AFE031; the DAC value output is filtered and amplified. In this mode, a sine table is cycled through, and each point is sent to the AFE031 over SPI.

In PWM mode, the SPI connection is only used to configure the registers for the AFE. Two PWM signals are generated and supplied to the AFE031 at the desired frequency for FSK transmission. The AFE will add these signals together to create a waveform that creates less harmonics than a single PWM signal.

Note that these two modes require different hardware configurations, so be sure to choose one or the other. If using the BOOSTXL-AFE031 test board as a reference, the hardware has been designed so that both modes can be used by simply adding or removing components.

When interfacing with the AFE03x as a receiver, the SPI connection is only used to set the registers of the AFE, much like the PWM transmit mode. The receive path of the AFE is enabled to allow the input signal to reach the ADC input of the C2000. Along this path lies some filters and two programmable-gain amplifiers (PGA) to step up or step down the input signal before entering the C2000 ADC.