Is there a "simple" example of how to write/read a USB drive using STM32CubeIDE?

[RCooke88]

Hi Folks,

I'd like to find an example of accessing a USB drive using the STM32CubeIDE. I'm currently using the Nucleo-H7A3Zi-Q board.

I believe I have setup the hardware correctly using the device configuration tool but I can't seem to find a simple or concise example on how to develop the code.

I have downloaded the STM32Cube_FW_H7_V1.11.0 code and examples but it still seems more complicated than it should. I've looked at STM32Cube_FW_H7_V1.11.0\Projects\NUCLEO-H7A3ZI-Q\Applications\USB_Host\MSC_Standalone\ but I don't understand how (or what) to import into my workspace.

For a start I just want to be able to write a "Hello World" into a file on the USB key.

Anybody have a good tutorial or example I can use?

Thanks,

Richard

[RCooke88]

I do have another question - Where does the following code belong:

if(usb_status>0)	// if usb mounted
  	{
  		fresult = f_opendir(&dir,USBHPath);	// main dir open
  		fresult = f_readdir (&dir, &file_info);
          }

Does it go before or after the case statements?

if(Appli_state == APPLICATION_READY && usb_status == 0)

[AScha.3]

TRY...debug.. breakpoints at f_mount , and opendir -> see fresult ok ? (= 0 ) ... ???

[AScha.3]

Hmmm..   the Appli_state ... is , what the usb telling us. Not more. ( at end of while loop, after 

/* USER CODE BEGIN 3 */  , as i showed.  )

Then in main, in the "while" loop, we wait (do ...nothing or something..) until usb is ready.

So i use here: "if mounted" -> then we can read or do more , before its mounted (maybe 100ms or so) any access would be useless, crash or at least some error. -> in main while(1) loop then !

[RCooke88]

usb_status = 0

Appli_state = APPLICATION_IDLE

fresult = FR_OK

[RCooke88]

After I step thru the while() loop a few times the Appli_state changes to APPLICATION_READY. But it never changes from that.

[AScha.3]

First : debug.. breakpoint at f_mount ; if connect to stick, you landing here . Then mount should work also.

If not ...check your hardware : is usb stick there? is 5V at the plug ? (i dont know...i dont have this board, just my own boards); see circuit of your board, maybe this "activate vbus.." is wrong, or the PF10 (enable vbus) not switches 5v to the plug, or need a jumper setting...is 5V there ?

[AScha.3]

Aaa...you should not "step" the while loop, this usb thing needs enumeration and so on...complex...it will need many times call the usb_host process, so dont break this processing. We only look for the result, just run and use breakpoint at ...mount . If it not coming there, then we look, why.

[RCooke88]

OK, I removed the breakpoint and just let it run for a minute and then I inserted the breakpoint.

Now the variables are:

usb_status = 1

Appli_state = APPLICATION_READY

fresult = FR_OK

Are we on the right track?

[RCooke88]

One more thing - The VBUS LED is on which I believe indicates that the USB voltage is on and within limits.

[AScha.3]

Yep. usb_status = 1 -> mount  = ok. 

Should do...what you want , now. But first try to read only, check filename is correct ...

and breakpoints can be at mount or read from beginning on, just let it run , until there, thats all.

+ i am on track to my bed now. 🙂