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I’ve been reading through the data sheet and have been having trouble finding an answer. I’m looking to use this to communicate SPI between a 5V mcu and a 3V3 device. Can the TXB shift the 5V to 3V3 for CS, MOSI, and SCK while shifting 3V3 up to 5V for MISO? I’ve been told other bidirectional level shifters can’t do this. Or am I better off just using an MCU with TTL so 3V3 from MISO can act as high without being level shifted.

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    \$\begingroup\$ The TXB works, if you care for all the restrictions that the datasheet tells you about. SPI uses unidirectional signals, so you would be better off with the TXU0304. \$\endgroup\$
    – CL.
    Commented Jun 27, 2023 at 19:17

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Yes it can, in general. When used correctly under the operating conditions stated in the data sheet. Which you don't state, so it is unknown if you can use it for your specific purpose. Most questions here about TXB0104 and similar are about why it does not work for them. But usually they were not used under correct conditions.

It is unclear why you were told other level shifters can't do what you ask, of course there must exist a level shifter another than TXB0104 that will work. Such as all sibling models maybe.

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  • \$\begingroup\$ I’m trying to use a 328P to communicate with an RFM69HCW, which is a 3V3 board. Truthfully, I’m not sure what other conditions are important to consider when trying to figure out if it would work or not. I’ll look back at the data sheet. \$\endgroup\$
    – 1W0n_29
    Commented Jun 27, 2023 at 20:35
  • \$\begingroup\$ @1W0n_29 Also consider running the (ATMEGA?)328P at 3.3V, assuming a number of other things work out of course. \$\endgroup\$ Commented Jun 27, 2023 at 20:38
  • \$\begingroup\$ @1W0n_29 Wiring length, load capacitance, drive strength, slew rate, all these must be withing limits or it won't work properly. \$\endgroup\$
    – Justme
    Commented Jun 27, 2023 at 21:27
  • \$\begingroup\$ @Justme gotcha, thanks. \$\endgroup\$
    – 1W0n_29
    Commented Jun 27, 2023 at 22:25
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    \$\begingroup\$ @TimWilliams I considered it, but I have other 5V devices that I need to use in the system as well \$\endgroup\$
    – 1W0n_29
    Commented Jun 27, 2023 at 22:27

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