nRF52840 receive USB command under Mass Storage

[Damien ALTMANN]

Hello Everyone,

I search a lot of time but I don't find any solution.

I looking for a solution to send "command" when the nRF52840 have an USB Mass Storage configuration.

We use the SDK 15.3.0 and the mass storage works fine.

I search some information about SCSI command and UFI command but under the SDK, I never find nothing.

So, I don't know if it's possible but I needs some help or some "link" to find the better solution.

Thank you a lot to everyone and I hope that it exist a solution.

Best regards,

Damien

[Kenneth]

Hello,

I have not looked into the USB specification for mass storage class; whether there may be some way of sending some (I assume) proprietarty commands while enumerated as a msc device. Assuming that is not possible I see two ways forward:

- add for instance the cdc (com port) class to device, then you can send commands through a terminal window.
- create a file name (e.g. my_hidden_commands.txt) that the device can read when updated to check for commands.

In both the above implementation I would recommend you to swap to the nRF Connect SDK, since the nRF5 SDK is no longer actively devloped on, ref:
nRF Connect SDK and nRF5 SDK statement 

Kenneth

[Damien ALTMANN]

Hello Kenneth,

Thank you for your response.

Yes, I imagine a solution to switch/reset between a USB CDC and a USB Mass Storage...but it's not easy.

Now, we can't switch to the new nRF Connect SDK but, perhaps, in the future, we will be able to switch, it's a good idea.

Thank you again. Best regards.

Damien

[Damien ALTMANN]

Hello,

I have another question, I found this link
RE: nRF52 APP_USBD_EVT_DRV_RESET event received instead of APP_USBD_CDC_ACM_USER_EVT_RX_DONE
who describe a error on the write/read file into the SD....but this example show that the USB Mass Storage and the USB CDC are enable in same time....

Is it possible ?

(I try to enable the MSC + CDC but in my case, it's not working yet.....)

Have you example with this 2 USB driver in same time ? (I use the SDK 15.3. now).

Thank you and best regards,

Damien

[Turbo J]

It is possible to use CDC and MSC at the same time, but it requires you to understand what the code is actually doing.

You need

1. IAD (Interface associaltion descriptor) because you no longer can use default USB class as MSC and CDC collide
2. Assign different endpoints since the interfaces each use their own

This is a lot easier in the newer Zyphr based SDKs, IIRC supported out-of-the-box.

[Damien ALTMANN]

Thank for this description.

I looking for some information about the IAD part in the SDK 15.3.0 but I don't find some example...

(only the APP_USBD_CDC_ACM_DEFAULT_DESC to define some class description but I don't know how use it...)

In the actual product, we can't change the SDK to the Zephyr (it's a lot of works for now)(but for the futur, we switch to the Zephyr base certainly).

-> Have you an example about the IAD with the SDK 15.3.0 ?

Thank you again. Best regards,

Damien