Clock for ULPI PHY?

[eleventen]

Posted on February 16, 2012 at 22:17

Greetings,

We're having a hard time telling whether or not the STM32F207 will drive the clock for the PHY.  There is a sentence in the datasheet that says, vaguely   External HS or HS OTG operation supporting ULPI in SDR mode. The OTG PHY isconnected to the microcontroller ULPI port through 12 signals. It can be clocked usingthe 60 MHz output.Does this mean we have to use one of the MCO outputs?  Or will the ULPI clock be driven at 60MHz?

[Tesla DeLorean]

Posted on February 16, 2012 at 22:31

We're having a hard time telling whether or not the STM32F207 will drive the clock for the PHY.  There is a sentence in the datasheet that says, vaguely

External HS or HS OTG operation supporting ULPI in SDR mode. The OTG PHY is connected to the microcontroller ULPI port through 12 signals. It can be clocked using the 60 MHz output. Does this mean we have to use one of the MCO outputs?  Or will the ULPI clock be driven at 60MHz? Or PA.5 OTG_HS_ULPI_CK 12-pin interface CLK    PA5 DIR    PI11 STP    PC0 NXT    PH4 D0    PA3 D1    PB0 D2    PB1 D3    PB10 D4    PB11 D5    PB12 D6    PB13 D7    PB5

[eleventen]

Posted on February 16, 2012 at 23:27

We're having a hard time telling whether or not the STM32F207 will drive the clock for the PHY.  There is a sentence in the datasheet that says, vaguely

External HS or HS OTG operation supporting ULPI in SDR mode. The OTG PHY is connected to the microcontroller ULPI port through 12 signals. It can be clocked using the 60 MHz output.Does this mean we have to use one of the MCO outputs?  Or will the ULPI clock be driven at 60MHz?

Or PA.5 OTG_HS_ULPI_CK

According to the UPLI spec, this line can be driven by the MCU or the PHY.  We just want to know that the MCU *does* drive it.  The RCC clock tree doesn't give me any place to configure a PLL or divider to get the 60MHz clock.

[Tesla DeLorean]

Posted on February 16, 2012 at 23:54

''The USB OTG HS (60 MHz) clock which is provided from the external PHY''

The STUPLI01B outputs 60 MHz, generated via it's external 26MHz crystal http://www.st.com/internet/analog/product/189049.jsp Presuming your part is running at 120 MHz, MCO1 = PLL / 2,  60 MHz MCO2 = PLL / 2,  60 MHz MCO2 = SYSCLK / 2, 60 MHz