USB overrides GPIO settings for DP/DM pins, in 'L452, too

It’s long known that in ‘F4, if the USB/OTG’s PHY is switched on, it overrides the GPIO settings of its DP/DM pins.

Today, I’ve spent some quality time debugging hardware, having been bitten by the same thing on a ‘L452.

I didn’t expect this, given entirely different USB module.

Neither of these is documented, of course.

Maybe it will spare somebody other’s time.

And maybe ST will document it, one day. It’s only^H^H^H^Hnot even 12 years since that first post, after all.

JW

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