> - This protocol seems terrible for throughput due to turnaround > latency. USB, for example, will necessarily introduce a one frame > (1ms) or one microframe (125μs) latency every time you're waiting > on > a direction change. The FT2232 (used in the Econotag) will also > add > a 16ms latency before flushing short transfers to the host, by > default. So any time you transmit a packet, you could end up > waiting an extra 16ms for the response. Instead of trying to tweak > those types of details on a per-device basis, it would be better to > not require a per-packet direction change in the protocol. You > could add fancy pipelining that allows multilpe outstanding > unacknowledged requests, or maybe just add some "transmit > unacknowledged" and "receive unacknowledged" style commands > that don't require waiting on a response.
Hi All, About the serial protocol latency over FTDI USB-to-serial converters and using the SLIP or COBS framing one could make use of the programmable event characters: http://www.ftdichip.com/Support/Documents/AppNotes/AN232B-04_DataLatencyFlow.pdf About a low latency protocol for USB sticks with an USB controller like the Atmel RZRAVEN or the TI CC2531, one could use a vendor specific protocol over HID. I tried this approach with the RZRAVEN and, even if the throughput over USB is limited to 64 bytes/ms, is should be enough to cope with the 802.15.4 throughput. I started doing this having in mind to operate the HID radio from userspace (and request/response turnaround time is really in the order of 3ms) using hidapi but maybe the HID radio can be also operated from the kernel (no idea how to that anyway). Just and idea... Regards ------------------------------------------------------------------------------ Rapidly troubleshoot problems before they affect your business. Most IT organizations don't have a clear picture of how application performance affects their revenue. With AppDynamics, you get 100% visibility into your Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro! http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk _______________________________________________ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
