Hi,
We will soon be using the Nios II as embedded controller and we would
like to add a High Speed (HS) USB 2.0 hosting feature that is capable
or providing a sustained transfer rate of 20 MBytes/sec. to an external
HS USB 2.0 device.
I realize that there are a limited number of HS USB 2.0 hosts
devices/IP cores currently available. The Phillips ISP1761 is the only
HS USB 2.0 component I was able to locate so far and it's not clear to
me if this part is readily available. Also, the
FPGA-based HS USB 2.0
host IP cores look like they are just now becoming available
(
www.asics.ws) but they may be cost-prohibitive.
Can anyone share their experiences in implementing either a HS USB 2.0
or Full Speed (FS) USB 1.1 host? Is a sustained transfer speed of 20
MBytes/sec. achievable with the assumptions that there are no major
transfer bottlenecks in the HS USB 2.0 host component or the associated
HS USB 2.0 device (e.g. USB Hard Disk). If not, what is a more
reasonable transfer speed goal that has a high probability of success?
The choice of which OS with Nios II (or no OS at all) may also be
influenced by the max. sustained HS USB 2.0 transfer speed that can be
achieved. However, it's also possible that in order to meet the 20
MBytes/sec. goal, the Nios II will have to be "removed" from the data
I/O path so that custom
FPGA circuitry can handle the transfers
directly with the external HS USB 2.0 host transceiver or the IP core.
Any information and/or opinions would be helpful.
Sincerely,
Brad.