stm32L452CEU6 usb doesnt work with Samsung GalaxyTab A8

[anees]

I have a board design based on stm32L452 , USB gets recognized on a windows PC and I can talk to the device over any software like putty and a Test software sees the com port and can to the device. However in Android (Iam using samsung  GalaxyTab A8), usb is not even recognized. The Tab support OTG mode and I did change default USB mode in the tab (Tried all the combo, file transfer, teethering, media etc). Nothing helps. Any advice is greatly appreciated

[anees]

Thanks, we are updating the code as per your suggestions and about to try. One other information is that USBCRS_SYNC (PA10 AF10 function) Is routed in the board to connector. But the USB cable do not have any pins for this? And datasheet doesnt explain what USBCRS_SYNC pin do? can anyone explain about this pin

[AScha.3]

Just from circuit nucleo-L4xx :

PA10 -> USB_ID , but not needed for device only.

[anees]

Iam confused, as per data sheet PA10 is  USB_CRS_SYNC,

[anees]

Does this mean this pin is needed for working with Android Tablet? wondering why it has no issue with windows/Mac

[AScha.3]

Me too 🙂

crs_sync seem needed for crystal less -> sync the HSI48

IF you select it as sync source :

from rm:

[AScha.3]

No, nothing about "Samsung" here. 🙂

IF you select it as sync source (see my last post) you need it as sync input . (If you use crystal less.)

>wondering why it has no issue with windows/Mac

Just lucky. Connect it to 10 different PCs , maybe 8 work, 1 sometimes, 1 never . (Without sync used to adjust the HSI.)

Thats why i wrote : try with HSE ---> usb-clk. Just to  exclude the clock problem.

IF using crystal less , use ->

[anees]

Was using HSI crystal less , as you suggested changed to  HSE ---> usb-clk ...

No impact, works in mac/windows but not in android. With this change,  may be I saw unknown usb detect error from windows few times.

Also tried changing USB_CRS_SYNC to RESET_STATE in ioc. In our board even though this signal is routed to USB connected, usb cable doesnt take this anywhere.  So still fighting the not able to talk to android issue.

What else can be tried? Should we try as a USB mass storage and see if android can detect that to isolate if its on android side or device side?

[AScha.3]

>Should we try as a USB mass storage and see if android can detect that

Why not ? --- easy to check .

Other way ---> check, whats coming from host (PC first, then Tab ) and what your device answers...

Might be some help, to see the debug messages from USB lib : do you have SWO usable ?

If debug enabled in HAL/usb lib, as host i get from swo : 

[jaindevasy]

Mass storage class showing same issue, detecting on Windows, but not detecting on Android.

The external clock (HSE) using now.

Below showing the schematic in which USB_DM and USB_SYNC is interchanged. Is there any possibility to work the USB in windows, if this pins are interchanged?

[AScha.3]

>Is there any possibility to work the USB in windows, if this pins are interchanged?

No - hey, but everything is possible in certain reality. 🙂

If really mixed up - correct it. And try connection then...