On Fri, 1 Mar 2002 14:18, Shane Nay wrote: > Situation- > I have a ARM board that I wrote a small USB stack for so I could > download my updates quicker. I wrote a linux driver to talk to that > USB stack and download my code basically. If you have a SA1110, there is a standard "usb device" driver that works with the usbnet driver, and a cdc ethernet driver that will soon work with the CDCEther driver. Why not just use those?
> Problem- <snip> > Now, I've hooked all this up to my osciliscope, and here's what I'm > seeing- > Case 1- One URB queued at a time > Frames are 1ms apart, traffic looks like- > [data]1ms[control]1ms[data]1ms[control] ... > > Case 2- Two URBs queued up at a time- > [data]1ms[data]1ms[control]1ms[data]1ms[data]1ms[control] ... Are you doing synchronous transfers? > Now, the problem is that the theoretical maxima I could get in this > scenario is 512kbps. However, both the PC and the device are capable > (hardware wise) of transferring a lot faster. (USB1.1 device, so in > theory 12Mbps) So, what do I need to do in order to ratchet up the > frame rate?, or just have it trigger the next transmit on the irq for > bulk completion? You should be able to just dump big data segments into the URB, and it will crank out. Look at Chap 5 of the USB spec and the Cypress white paper on throughput to see why the real limit is not 12Mbps, but more like 8 or 9 Mbps on an otherwise unloaded bus. Sorry this isn't helping much... Brad _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
