USB_OTG PORT IS NOT DETECTING

[dibing]

Hi,

We designed a monitoring system using IMX6ULL processor. USB_OTG1 port is using for loading the Kernal.

USB_OTG1 was able to detect before loading the uboot and kernal. After loading the kernal for first time (failed after copying almost complete directories) the USB port became disable. Now MFGtool does not detecting the USB port.

How can we access the USB port ?

Observations:

1. USB_OTG_CAP power rail is 3.2V -  after power up, this internal voltage rail is changing from 2.6V to 2.8V, 3V and then to 3.2V

2. voltage level of USB_OTG1_DP is initailly 0.5V and then reducing to 0V

[igorpadykov]

Hi Dibin

if MFGtool does not detecting the USB at all (even after board power-up),

one can check 24MHz crystal and follow check list described in i.MX6ULL Hardware Development Guide 

https://www.nxp.com/docs/en/user-guide/IMX6ULLHDG.pdf

If it is not detecting after starting linux, this may be driver issue, one can try

nxp official releases from repository linux-imx - i.MX Linux kernel 

Best regards
igor
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[dibing]

Thanks, the 24MHz crystal is working properly.

Still I have the doubt that, why the USB port is not detecting once the kernal is loaded ? If there is any driver issue, how it is possible to load the kernal ?

Voltage level of USB_OTG1_DP is 2.75V in properly working board. For the board which is not working properly, it is initially 0.5V and then reducing to 0V (When USB port is unconnected).

Is it okay?

[igorpadykov]

if this just one board this may be poor soldering issue or broken chip

(probably due to esd or overheating). One can try to replace it.

Best regards
igor

[dibing]

The board is booting from eMMC and getting the console properly. Even if the board configured for Serial download, it is booting from eMMC.

I have checked SRC Boot Mode Register 2 by varying boot mode switches and verified the Boot Mode [0:1] circuit is working properly.

USB OTG1 port is acting as Master and we need to get it as slave for loading new kernel image.

What will be the problem in USB OTG1 interface?

[igorpadykov]

such behaviour may be if SD/MMC manufacture mode is enabled, described in
Figure 8-27. SD/MMC manufacture boot flow i.MX6UL Reference Manual
http://www.nxp.com/docs/en/reference-manual/IMX6ULLRM.pdf

Best regards
igor

[dibing]

How can I disable the SD/MMC manufacture mode?

[igorpadykov]

[dibing]

Can I disable the SD/MMC manufacture mode with using Boot configuration GPIO settings?

The same MFG tool image is working properly in another variant board which using the iMX6ULL.

[dibing]

No, for two boards which i tested show the same issue.

USB OTG1 is detecting USB thump drives, but cant detect it by MFG tool in serial download mode.

So I think, there is no such soldering or ESD issues.