IMX6UL pad drive strength(DSE) for USB_OTG1_DN, USB_OTG1_DP, USB_OTG2_DN and USB_OTG2_DP

[chpub70]

Hi NXP.

How to change the drive strength(DSE) for IM6UL pads USB_OTG1_DN, USB_OTG1_DP, USB_OTG2_DN and USB_OTG2_DP ?

Best Regards,

Pun

[igorpadykov · Accepted solution]

Hi Pun

drive strength can be configured for digital signals, not for analog as those usb signals.

For usb analog signals one can consider sect.4.3.3.2 Transmitter settings AN4589

Configuring USB on i.MX 6 Series Processors

Best regards
igor

[chpub70]

@igorpadykov ,

Hi Igor,

May I know how to change the bit of TXCAL45 of USBPHY_TX register, from Linux 3.14.52 ?

[igorpadykov]

one can use memtool:

https://source.codeaurora.org/external/imx/imx-test/tree/test/memtool?h=imx_5.4.70_2.3.0

Best regards
igor

[chpub70]

@igorpadykov

Hi Igor,

I encountered on with my own board with IMX6UL, these registers cannot be accessed if there is no USB devices connected. 

Could you advise ?

Best Regards,

Pun

[igorpadykov]

> these registers cannot be accessed if there is no USB devices connected

this may be due to usb low power mode (clocks may be switched off)

 

Best regards
igor

[chpub70]

@igorpadykov 

Hi Igor,

Also my usb device is a full speed device. Can I still tune D_CAL, TXCAL45 because AN4589.pdf shows only for high speed device.

Thank You in advance.

Best Regards,

Pun 

[igorpadykov]

> Can I still tune D_CAL, TXCAL45 because AN4589.pdf shows only for high speed device.

I am afraid not, sorry.

Best regards
igor

[chpub70]

@igorpadykov 

Hi Igor,

You mean for full speed device has to use default value for d_cal and txcal45 ?

[igorpadykov]

they are used in high speed mode only.

Best regards
igor

[chpub70]

@igorpadykov 

Hi Igor,

Is there registers to tune driving current and termination resistance for full speed device ?

Do you have any recommendation to tune for USB full speed device ?

[igorpadykov]

I am afraid there are no other options, except described in application note.

Best regards
igor

[chpub70]

@igorpadykov 

Hi Igor,

Also my usb device is a full speed device. Can I still tune D_CAL, TXCAL45 because AN4589.pdf shows only for high speed device.

Thank You in advance.

Best Regards,

Pun