Jim,

> Some 3.3v logic interfaces are 5v tolerant.

The question is: Should I bother to check the HC-05 datasheets, or does the
JY-MCU breakout board already handle it (which I thought it was there for) ?

> Often a resistor (I've seen 1Kohm mentioned) directly in the signal line
> is enough to prevent damage. AFAIK it uses the, often, inbuilt powerline
> protection diodes - but I'm sure a more comtetant HW guy could spell
> chapter and verse.

Yes, I'm aware of that possibility.

The thing is that currently I cannot find *any* information on what the
JY-MCU breakout board does or doesn't do (like does it already have such a
series resistor in place ?) - or even what its STATE and EN pins are
supposed to be there for. Which is the whole problem.

And yes, I could spend some time trying to trace some of the tracks on the
breakoutboard to the components on it (by eye or ohm meter) and than do /my
best guess/* to what is going on, but that is definitily NOT the way it
should be going.

*and hope that its good enough!.

Currently I feel like I've been had, as if I've bought myself a cheap
throw-away gadget. :-(

Regards,
Rudy Wieser

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