Voyantic

Chip Performance Measurements with Voyantic Tagformance: Write Time Test

Application Note

Published 2013
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1 Introduction

Chip performance has (at least) three aspects: the read sensitivity, the write sensitivity and the write time. The last means how long it takes to complete the write operation. In this application note you will learn how to test this with Tagformance.

2 Getting Started

To follow this Application Note you should already have the following:

  • Tagformance System set up for tag measurements
  • Software license for Protocol Testing Suite (in case you do not, please contact sales@voyantic.com for free evaluation license)
  • The tag containing the chip you want to test
  • EPC Global Class 1 Gen 2 protocol handy and basic understanding about it.

3 Testing the Write Time

  1. Place the DUT in suitable position. E.g. 30 cm away from the measurement antenna and in correct polarization. The Measurement Setup in Tagformance does not need to be set as we do not use calculated units such as power on tag forward (sensitivity) or read range with Protocol Testing Suite.

  2. Set the carrier frequency and power so that the tag will have about 10 dB excess power. To find out how much you need you can first run Threshold sweep using write command. Then pick a frequency you want to test on. Then look at the y-axis value Transmitted power on that frequency and add e.g. 3 dB to make sure your write should always be successful.

  3. Start carrier.

  4. Run inventory.

  5. Select RegRN command.

  6. Click send command.

  7. Create write time test command:
    Preamble: Frame Sync
    Name: e.g. write RN16 as EPC 1st word
    Command: 11000011 (write)
    Parameters: 01 00000010 0000000000000000
    where:
    01 = EPC bank
    00000010= word pointer, first word of EPC code
    0000000000000000 = data XOR RN16 from tag as response to RegRN in previous step; with 16 zeros the data to be written will be the received RN16
    Handle: use handle
    CRC: 16-bit

Click ADD to add this command in the COMMANDS list.