Re: gEDA-user: FT232R

[Ben Jackson <ben@xxxxxxx>]

On Wed, Apr 08, 2009 at 07:17:06PM -0500, Bill Gatliff wrote:
> 
> Point is, I can't refute either a 100% success or stay-away-at-all-costs 
> claim for either device.  USB-powered devices in general demand good 
> decoupling and filtering on VCC, and maybe FTDI-based products that fail 
> to do that will cause problems.  But so would just about everything 
> else.  YMMV.

My main reservation about FTDI is that outside the "USB serial" mode the
devices are very focused on write-only behavior.  They don't really give you
good tools for doing bulk reads.  So if you want to pump data INTO a system
(eg the common FTDI based JTAG cable) FTDI is a fine choice.  If you want
to get bulk data OUT it's another thing entirely.  In fact, without the
Linux drivers I think my project would have failed (turns out the windows
drivers actually start a task which periodically flushes the input even if
you don't consume it -- the more debug prints I added the worse things got).

These days I'd see if I could get a USB AVR to do what I needed.  I just
used one to make a gamepad (keyboard device) and it was great with the
LUFA library.  If I needed bigger guns I'd probably use one of the Cypress
micros (I think the GNU radio guys use one of those to pump data to/from
a Cyclone FPGA).

-- 
Ben Jackson AD7GD
<ben@xxxxxxx>
http://www.ben.com/


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