Re: seek for help on Libusb & STM32

Best regards,
Pradeepa Senanayake.
On Mar 10, 2014 9:00 AM, "Pradeepa Senanayake" <[email protected]>
wrote:

> Hello Duan,
>
> Since the firmware you use is for a VCP it will be enumerated within the
> PC side as a COM port. In that case you can directly use serial writing
> methods to access the device. I don't think that you need libusb in that
> case. But if you wan't to have lets say a Vendor Specific class with your
> own descriptors (ie. Endpoint types, etc. ) then LibUSB will come in handy.
>
> For your application, if COM port is enough, I would recommend using
> methods to access COM port rather than using LibUSB. Do a google search
> with keywords such as " Writing to a COM port using visual studio" and you
> will get plenty of hits.
>
>
> >>   I  learned  you had done similar works from here
> >> https://sourceforge.net/p/libusb-win32/mailman/libusb-win32-devel/thread/CA+1tQ71CeMubpzV2rBHPnWQ5Zcnihx1e>>>>
>   [email protected]/<https://sourceforge.net/p/libusb-win32/mailman/libusb-win32-devel/thread/CA+1tQ71CeMubpzV2rBHPnWQ5Zcnihx1e24_1wqFHicofGqsi0Q@mail.gmail.com/>
>
> In the above link, he is not using VCP. That is why it is easier to use
> LibUSB. I'm just a LibUSB user (not a developer) so the devs will correct
> me if I am wrong.
>
> Please refer to this discussion,
>
> http://sourceforge.net/p/libusb-win32/mailman/message/31338949/
>
> it will hopefully clear most of the doubts.
>
> Hope I helped.
>
> Thank you,
>
>
>
> Best Regards,
> Pradeepa Senanayake.
>
>
> On Sun, Mar 9, 2014 at 2:22 PM, Duan Xiudong <[email protected]> wrote:
>
>> Hello   Pradeepa,
>>
>>      I am a student form China. I'm trying to get some data  using USB
>>  from a board based on STM32F4xx chips. Right now I'm trying it on  a
>> STM32F4discovery  board.
>>
>>     On  the  device side,  I  implement a  Virtual COM Port project form
>> ST firmware.It can work well as a COM port with PC.
>>
>>     And now I download  libusb-win32-1.2.6 , generate and install the
>> drivers (INF file) as  it requires. Then I  test  it on VS  using the
>> example code from the official  website. It seems  that PC can get the
>> configuration information correctly,  but can not execute  any bulk_read
>> operation. When it runs to * usb_bulk_read()* or *usb_submit_async()*
>> function, the program ends with error.
>>
>>     I  don't  know where the problem is.  Is there any problem  on PC
>> side codes?  OR something  wrong  with device firmware? It puzzled me a lot.
>>
>>        I  learned  you had done similar works from here
>>
>> https://sourceforge.net/p/libusb-win32/mailman/libusb-win32-devel/thread/CA+1tQ71CeMubpzV2rBHPnWQ5Zcnihx1e24_1wqFHicofGqsi0Q@mail.gmail.com/
>>
>>       I hope you can give me some instructions. If you're kindly  to
>> offer some help, I will give more details.
>>       Thank you very much!  Hope  for  your  reply.
>>
>> --
>> Daniel
>>
>
>

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