I2C/external FS PHY on USB_OTG_HS in STM32F407

[waclawek.jan]

Posted on June 09, 2017 at 13:31

'F407's OTG_HS_GCCFG:

The USB OTG HS core embeds an I2C interface allowing to connect an external FS PHY.

The I2CPADEN is used to enable or disable the I2C bus connection for this interface.

On which pins?

Can you please give an example of such FS PHY and its connection to the 'F407?

Thanks,

Jan

[Split from

https://community.st.com/thread/40934-stm32f4-usb-fs-and-pa8-as-output-not-working&sharpcomment-159423

]

null

[Khouloud GARSI]

Posted on June 16, 2017 at 15:43

Hi

Waclawek.Jan

‌,

I have checked internally and the OTG HS interface does not support an I2C interface allowing to connect an external full-speed PHY.

This information will be removed from the reference manual.

The OTG HS interface supports:

• An on-chip full-speed PHY
• An ULPI interface for external high-speed PHY.

Sorry for any inconvenience this may have caused.

Khouloud.

[waclawek.jan]

Posted on June 16, 2017 at 16:13

Hi Khouloud

Thanks for the info.

Jan

[waclawek.jan]

Posted on July 25, 2017 at 11:36

This has NOT been updated in RM0090 Rev.15; both Chapter 35.3.2  and I2CPADEN description are still there.

JW

[waclawek.jan]

Posted on October 06, 2017 at 12:03

I was able to get the I2C on OTG_FS working, so at least this funcionality *is* implemented. The rest, required to properly connect a FS_PHY (such as ISP1302 or STOTG04ES) may not be implemented, and is of no interest given the internal PHY; but the I2C itself provides an interesting addition to the existing peripherals, even if its a single-register-read-write, single-speed master-only design.

It would be nice if ST would document its functionality. These are transistors we are paying for.

JW