On Fri, 8 Nov 2002, Boris Dainson wrote: > > 48ms...? I thought you said 9-12ms per syncSubmit...? >> >> So, I'm confused - does I2C require sending a 1-byte submission, 20 times? >> Or do you send a single 20 byte submission, that takes a full second to >> finish? And if so, is the USB subsystem causing the delay, or I2C...? >> > >Right, it 9-12 for syncSubmit(). > >To complete an I2C read operation (1 byte of I2C data) you'll need 4 of such >syncSubmits or 48ms. Higher level app may need to read 20 bytes over I2C as >a full telemetry packet which adds up to 80 synchSubmits or 960ms.
Ah, ok. I think it'll be hard to get each submit faster than 12ms, but it may be possible. Isn't it possible to read multiple bytes at once, or at the least use asyncSubmit? Async wouldn't reduce the latency for any specific submission, but would reduce the overall latency. Does each I2C read depend on the last one? If not, use async, at least for all but the last read. -- Dan Streetman [EMAIL PROTECTED] --------------------- 186,272 miles per second: It isn't just a good idea, it's the law! ------------------------------------------------------- This sf.net email is sponsored by: See the NEW Palm Tungsten T handheld. Power & Color in a compact size! http://ads.sourceforge.net/cgi-bin/redirect.pl?palm0001en _______________________________________________ javax-usb-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/javax-usb-devel
