waclawek.jan

[OTG + documentation] OTG overrides GPIO

Discussion created by waclawek.jan on Oct 6, 2017

When OTG_xx_GCCFG.PWRDWN = 1, the respective OTG_xx_DP and OTG_xx_DM pins are not controlled by GPIO anymore - after setting their respective MODER to Out, the output levels don't follow changes in respective ODR.

 

This one has been spotted by Olov Rosén (and possibly others in the past)  and explained by Arsenii Soitu, I am just confirming that I have been able to reproduce it on 'L476, and on 'F407 both OTG_FS and the FS-PHY of OTH_HS.

 

ST, please comment. If confirmed, please add to the GPIO chapter of RMs - this is an unexpected and surprising behaviour, as the modules are not supposed to control the pins unless set to AF mode and proper AF selected (the oscillator pins being the documented exception (and the 'L4xx PH0/PH1 erratum being the exception from exception :-) )).

 

JW

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