On Tuesday 19 December 2006 5:33 am, Patrik Nagel wrote: > Meher wrote: > > Patrik, > > As much as I know about USB controller used on davinci, it does > > not support multiple ISO transfers per frame. The description above > > states that you can send maximum payload of 1024 bytes in a single > > transfer. > > Meher, thanks for your reply. So, is there another way to realize an iso > endpoint with a data rate higher than 150 Mbit/s ?
You did the math already. The limitation is in hardware, and can't be worked around without updated hardware. To get more than 150 Mbit/sec you'd need real high bandwidth support, with almost three max size packets per microframe. There is such an option for the licensed IP core, but I wouldn't know if TI has it ... or has plans to re-spin the silicon with changes like that. (If it did, I'd really hope to see fixes to the CPPI DMA engine, which has also been a bottleneck.) - Dave > Or is the maximum transfer speed limited to 65 Mbit/s [1 ], i.e. the > maximum for a single high-speed iso endpoint ? > > regards, > Patrik > > [1] > 8000 * 1024 * 8 = 65 Mbit/s > (one microframe per 125us with a payload of 1024 bytes) > _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
