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Peter Stuge peter at stuge.seHarald Welte wrote: > > Basically the USB "framework" would need to be rewritten specifically > > for zero copy operation, if the hardware actually allows that. > > unfortunately the old USB peripheral in the sam7s does not have DMA, you > have to use FIFO / MMIO to put the data onto USB. It's really sad, > almost all other peripherals can do DMA, but not the USB device > controller. I figured as much. Perhaps writing to the FIFO can happen already when initially receiving the data from the serial port, ie. without first storing to a buffer in RAM. But I think this will have some non-trivial consequences for the code. //Peter