115200 bps is ~ 14 k/s. At that speed, a full 256Mb ram dump would
take approximately 5.2 hours.
...
Compression's a good idea.
What about one of FTDI's USB - FIFO converters? (or USB-UART)
the FIFO ones have
"Data transfer rate to 1 Megabyte / second - D2XX Direct Drivers."
or
"Data transfer rate to 300 kilobyte / second - VCP Drivers."
I am not quite sure what D2XX or VCP means, but you can get D2XX for
Mac OS X, Linux, etc.
http://www.ftdichip.com/Products/FT245R.htm
or something like this for testing, in case we don't want to
integrate on board:
http://www.sparkfun.com/commerce/product_info.php?products_id=7841
(currently sold out, there is a demo board on FTDI site)
at one megabyte per second, we can transfer all 256 megabytes in
approx 4 min, 16 seconds.
Of course, we won't be able to constantly achieve these speeds, but
that is what they say is max rate.
If there is nothing else attached on that USB bus, it will probably
be able to get close to constant 1 MB/sec.
We should probably still have some compression on board, just in case
that is a bit high for an estimate.
There is also a so-called "USB to UART Switch" manufactured by Dallas/
Maxim Semiconductors
that can switch the two signals - this would be useful for having
both, but just USB would probably work.
nick
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