Hello. I'm trying to connect the module HM55B (electronic compass) with MCB 2378. The module operates at 5 volts and I want to connect FAST GPIO pins that go to 3.3 volts. How I can do? Thank you very much
"says the same (5 v)."
The ones I found clearly said that the chip itself was 3V3 - the module is supplied with 5V, but has an onboard regulator that drops this to 3V3.
Maybe you have a slightly different variant of "HM55B (compass sensor)" - so you need to provide links to the actual documents that apply to the actual version of the actual part that you're actually using.