To use the fixture,

  • Remove power from the fixture
  • Place the device to test in the fixture and lower the toggle
  • Apply power from the fixture and wait for the test result
  • Remove power from the fixture
  • Remove the device from the fixture

The test program depends on the device you are testing. For instance, if the board should contain an I2C device at address 68, then the very simplest test program might say (in pesudocode)

  1. Set NeoPixel to BLACK
  2. Initialize I2C bus
  3. Scan I2C bus
  4. If address 68 is present: Test is successful; show GREEN on neopixel
  5. Else: Test fails, blink RED on neopixel

A more production-ready test fixture might:

  • Be designed so that the device under test can be safely hot-plugged, so that the whole fixture does not need to be power cycled
  • Perform a test of more functions of the device besides I2C detection
  • Include a buzzer and/or a display for test results
  • Include purpose-built circuitry specific to the device (either built in the prototyping area or on a custom PCB)
  • Omit the unnecessary pogo pins (for example, an I2C Feather might only connect SDA, SCL, GND and 3V3 pins)

Want to know more about what goes into designing a professional test fixture?  Check out this video by Ladyada:

This guide was first published on Dec 11, 2020. It was last updated on Dec 11, 2020.

This page (Using the Fixture) was last updated on Sep 08, 2021.

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