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Unread 28-01-2012, 22:47
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Re: Interfacing 3.3 Volt Logic sensors with CRIO

Yes, you're correct that the 3.3V output won't trigger a 5V input.

Simple things which you've probably checked already:
  • You're supplying 5V to the IMU board? Sparkfun doesn't seem to have posted specs, but judging from the picture and schematic, it's got a 3.3V regulator.
  • The TXB0104 "Output Enable" pin is tied to 3.3V?
  • All of the unused inputs on your supply translator are grounded?

Hmm, nevermind. There's this little note on page 11 of the datasheet:
Quote:
The output drivers of the TXB0104 have low DC drive strength ... the TXB0104 should not be used in applications such as I2C or 1-Wire where an open-drain driver is connected on the bidirectional data I/O. For these applications, use a device from the TI TXS01xx series of level translators.
As a side note, be careful with your terminology: I was really confused for a while when you said you soldered your "logic bus analyzer". A logic analyzer, while possibly quite useful for what you're doing, is definitely not something you would solder.
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