2011-02-01 06:33:16     USB Serial Gadget speed

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2011-02-01 06:33:16     USB Serial Gadget speed

Nikolay Chokoev (IRELAND)

Message: 97840   

 

Hi,

 

Does the USB Serial Gadget emulates the actual RS232 baudrate (set by tcsetattr() for ex)?

 

What is the maximum supported speed (or what it depends on) ?

 

Regards,

 

Nikolay

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2011-02-01 11:13:48     Re: USB Serial Gadget speed

Mike Frysinger (UNITED STATES)

Message: 97846   

 

please review the documentation:

linux-2.6.x/Documentation/usb/gadget_serial.txt

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2011-02-01 12:19:47     Re: USB Serial Gadget speed

Nikolay Chokoev (IRELAND)

Message: 97847   

 

It says  "--these settings mostly do not matter.", but it looks like they don't matter at all.

 

If that's the case what is the speed it's running at? What's the maximum speed one can get and what it depends on?

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2011-02-01 12:22:25     Re: USB Serial Gadget speed

Mike Frysinger (UNITED STATES)

Message: 97848   

 

if the documentation doesnt explain it, then the source is the documentation.  i dont think we've looked at either of these aspects before.  i imagine it simply fills the USB pipe rather than putting useless artificial delays in.

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2011-02-02 04:31:59     Re: USB Serial Gadget speed

Nikolay Chokoev (IRELAND)

Message: 97868   

 

Thanks Mike. I just was wondering if somebody already looked at it. I think, as well, it doesn't put any delays, but there is an overhead running RS232 over the USB probably and the speed depends on what USB transfers are used (I suppose bulk). Probably the best way is to look at the sources...

 

Best regards,

 

Nikolay

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2011-02-02 15:20:17     Re: USB Serial Gadget speed

Mike Frysinger (UNITED STATES)

Message: 97871   

 

i dont know what your needs are, or what gadget driver you're using exactly, but there are "f_acm" and "f_serial" drivers.  the former tends to be more compatible with devices while the latter tends to be less overhead (that's my understanding).  if these still arent fast enough, you could try using the ethernet gadget ...

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