AVR-Chat

AT43USB355E price is u$4.50.  I am wondering if it
would be an appropiate device to develop a mixing
console with +32 knobs (potentiometers).  The device
has to measure the knobs position (thruough the ADC)
and send the values over USB.  Is AT43USB355E fast
enough to this application?

Regards,

Jose

 --- Joel Kolstad <jkolstad71@yahoo.com> escribió: 
> 
> 
> --- In AVR-Chat@yahoogroups.com, Kathy Quinlan
> <kat-yahoo@k...> 
> wrote:
> > I have the dev kit for the 355M, but I find it
> hard to use due to 
> lack 
> > of documentation and example code for beginners,
> but I am hopping 
> that 
> > after reading Jan ALexson's USB for embedded
> design (I think that 
> is the 
> > title) I will get a grasb on the subject and be
> able to do 
> something 
> > useful with them :)
> 
> You'll also want to check out the USB developers
> forum 
> (http://www.usb.org/phpbb/); there's been plenty of
> discussion there 
> about the AT43USB355E (and variants), and Jan
> Axelson shows up 
> occasionally as well.
> 
> I used the AT43USB355E to implement what was
> effectively a USB <--> 
> I2C interface with a few extra bells and whistles
> last year.  The 
> problem, at the time, was that the code that comes
> with the Atmel 
> development kit is heavily biased towards building a
> human interface 
> device such as an X-box joystick (this is what the
> AT43USB355E was 
> initally designed by Atmel to do!); they do NOT give
> you all the 
> source code you need to build a 'general purpose'
> USB device.  
> However, if you pester the appropriate people at
> Atmel (see the USB 
> IF forum for details), you CAN get all the source
> code except for 
> one file that contains the functionality of the hub
> in the '355E; 
> Atmel considers this proprietary, and given that no
> one else seems 
> to be handing out hub source code, that seems
> reasonable enough.
> 
> Overall, there's a lot more work if you use the
> '355E than if you 
> simply use an FTDI chip.  What you gain, however, is
> better 
> throughput (speed) in the system (compared to the
> serial FTDI chips) 
> and the ability to have your USB device looks like
> 'whatever you 
> want it to' rather than 'just' a serial port. 
> You're also adding 
> another chip with the FTDI approach, of course.  On
> the downside, 
> for the '355E you'll also have to write your own USB
> device driver 
> (highly non-trivial if you haven't done this before,
> although there 
> are toolkits out there that make this a lot easier
> if you can afford 
> them -- we used DriverX USB) unless you make the
> '355E look like a 
> human interface device (HID) -- which pretty much
> negates the speed 
> advantage that you otherwise would have gained.
> 
> Hence, if the FTDI chip will work for your project,
> unless you're 
> going into mass production (where the extra cost of
> the FTDI chip 
> more than pays for the added development costs), or
> unless you're 
> interested in learning a lot about low level USB
> (this was my 
> motivation), it's pretty hard to beat the FTDI
> approach.
> 
> BTW, there's a web site out there about a guy who
> implements a low 
> speed (1.5Mbps) USB peripheral strictly via 'bit
> banging' the I/O 
> ports.  Once you get done reading Jan's book, you'll
> realize just 
> how impressive that feat is!  Interestingly, he did
> it using one of 
> the older devices (this was a couple of years back),
> and since then 
> the newer devices such as the tiny2313 have come out
> with faster 
> clock speeds and more memory that would be even more
> attractive for 
> this purpose.  It's a HUGE amount of work to do this
> (the guy with 
> the web site said he spent six months working almost
> every night 
> after work getting to the point where Windows would
> recognize his 
> device), but it'd be a great benefit to the
> AVR-using community if 
> someone did.
> 
> ---Joel Kolstad
> 
> 
> 
> 
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
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> 
>  
> 
> 
> 
>  


	

	
		
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