SLOA247C July   2017  – March 2019 RF430FRL152H , RF430FRL153H , RF430FRL154H

 

  1.   Frequently asked questions for RF430FRL15xH devices
    1.     Trademarks
    2. 1 General Questions
      1. 1.1 What is the RF430FRL15xH?
      2. 1.2 What are the variations of the RF430FRL15xH?
      3. 1.3 What is the recommended hardware and software to evaluate the RF430FRL15xH?
      4. 1.4 I cannot purchase a TRF7970AEVM. How do I use the RF430FRL152HEVM GUI?
      5. 1.5 Does the RF430FRL15xH support NDEF messages?
      6. 1.6 What RF communication range can be expected with the RF430FRL15xH?
    3. 2 Hardware and Design Questions
      1. 2.1  What TI Designs are available for the RF430FRL152H?
      2. 2.2  How do I design and tune an antenna to 13.56 MHz for my application?
      3. 2.3  Why are the various external components required?
      4. 2.4  How much power can be sourced from the RF430FRL15xH?
      5. 2.5  What battery can be used with the RF430FRL15xH?
      6. 2.6  How should the switches be set on the RF430FRL152HEVM?
      7. 2.7  How can an external sensor be connected on the RF430FRL152HEVM?
      8. 2.8  What kinds of analog sensors can be used?
      9. 2.9  How can a digital sensor be used?
      10. 2.10 How can the internal temperature sensor be used?
      11. 2.11 What are the settings to program the RF430FRL152HEVM with an MSP-FET tool?
      12. 2.12 Is there a low-voltage programmer suitable for the RF430FRL15xH?
    4. 3 Software Questions
      1. 3.1 How is the RF430FRL15xH ROM library used?
      2. 3.2 What example firmware is available for the RF430FRL15xH?
        1. 3.2.1 Default Project
        2. 3.2.2 SensorHub Project
        3. 3.2.3 NFC Project
      3. 3.3 Is there an Android app available to interface with the RF430FRL15xH?
      4. 3.4 What is the procedure to change between 4- and 8-byte ISO/IEC 15693 blocks?
      5. 3.5 How can custom ISO/IEC 15693 commands be sent and received?
      6. 3.6 How can a simple SD14 ADC conversion be set up and executed, and the result read back?
      7. 3.7 Where is the software for the TIDM-RF430-TEMPSENSE EVM?
    5. 4 Miscellaneous Questions
      1. 4.1 How can the SD14 ADC result be converted to temperature?
      2. 4.2 Is there a way to program RF430FRL15xH over-the-air?
      3. 4.3 How can the battery-less NFC/RFID temperature sensing patch be used?
      4. 4.4 Is the RF430FRL15xH available as a bare die?
    6. 5 References
  2.   Revision History

4.1 How can the SD14 ADC result be converted to temperature?

The ROM library in the RF430FRL15xH does not calculate out the temperature. The device only provides the raw reference resistor and thermistor results as they come from the SD14 ADC. These actual results of the raw values are expected to be calculated on a device with more processing power and program memory space available, or with a look-up table.

The following example shows how the temperature is calculated for the RF430FRL152HEVM by an external reader. The equation in step 3 came from the thermistor data sheet. This equation converts from raw ADC result to temperature.

As part of the calculation of the temperature, the formula to determine the thermistor's resistance is required. This formula is provided in the thermistor resistance calculation section in the RF430FRL15xH firmware user's guide.

Definitions:

  • refValue is the reference resistor ADC result.
  • thermValue is the thermistor ADC result.
  • refResistance is the resistance value of the reference resistor, which for the RF430FRL152HEVM is 100 kΩ.
  1. tempConv = (thermValue / refValue) × refResistance
  2. Using the resistance from the previous equation, the temperature in Celsius is calculated.
  3. Temp in C = (1.0 / ((((Math.Log10(tempConv / 100000.0) / Math.Log(2.718))) / 4330.0) + (1.0 / 298.15))) – 273.15
  4. Temperature in °F = (Temperature in °C × 9 / 5 + 32)

Notice that the reference resistor result is also used in the calculation. This is needed to properly measure the current through the thermistor and reference resistor. When the current source is known, using the thermistor ADC result, the temperature can be calculated.