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USB ULPI register write

Posted: Sat Apr 01, 2017 8:03 am
by Davide
Hello, is there some documentation or example on how to write to an USB PHY configuration register with ULPI ? I would like to ask Microchip USB3343 to swap DM and DP pins. It's the second bit of this register :

7.1.3.5 USB IO & Power Management
Address = 39-3Bh (read), 39h (write), 3Ah (set), 3Bh (clear)

SwapDP/DM 1 rd/w/s/c 0b

When asserted, the DP and DM pins of the USB
transceiver are swapped. This bit can be used to
prevent crossing the DP/DM traces on the board. In
UART mode, it swaps the routing to the DP and DM
pins. In USB Audio Mode, it does not affect the
SPK_L and SPK_R pins.

http://ww1.microchip.com/downloads/en/D ... c/334x.pdf page 82.

Thank you :)

Re: USB ULPI register write

Posted: Sat Apr 01, 2017 4:34 pm
by Giovanni
Hi,

The driver itself does not help you in doing this, you may need to access OTP registers directly, see the STM32 RM for details, I am not even sure where to start, it is a lot of doc :)

Giovanni