On Wed, 1 Mar 2006, Mukund JB. wrote: > >In other words, since low-speed USB runs at 1.5 Mb/s, that's 1500000 > bits > >per second, or 1500 bits per frame, or 187.5 bytes per frame. Since > you > >can't transfer half a byte, the number is rounded down to 187. > > I agree for low speed devices, the max allowable bandwidth for all low > speed device put together is 1.5Mb/s. > > Please see last row of the table below: > > 8 24000 30% 3 19 24 --> last but one row > > As you said, for 8 bytes payload the max transfer possible are 3 and so > maximum bytes/Frame are (3*8) = 24 bytes. > In a similar way what are the values "payload" and "max transfers" to > get the bytes/Frame as 187. > > Max 187500 187 --> last row > > Hope I am clear.
There are no "payload" and "max transfers" values for the last line. That's why it's formatted differently from the rest of the table. The last line does not refer to control transfers; instead it talks about the theoretical maximum capacity of the bus. If it helps you to understand the table better, pretend the last line isn't there at all. Alan Stern ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
