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
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.