Flash ADC selection, or other approach?

Tom Jennings wrote: <snip> or funny hardware to talk USB (and I don't think USB will guarnetee me my latency) <snip> ------ The Cypress FX2 (CY7C68013) would, with the aid of a state machine to drive the sampling, (double) buffering and crank the byte stream into the FX2's FIFO, enable the continuous recording of your data stream. However, the FX2 EVB is ~$500, and as you note the SBC approach at $100 is cheaper. Nonetheless, the FX2 can (according to the specs) move up to 480Mb/s through the class drivers. There may be a cheaper FX2 platform or simply cheaper USB hardware available. However, it a capable and (programmer) friendly device, ideally suited to bridging between bespoke interfaces and a laptop. wrt latency, not even asynchronous logic will give you ZERO LATENCY. And, if I've understood the requirement correctly it is to acquire a finite block of data at a constant rate without gaps; so latency is not a system level requirement. hth, just putting the case for USB (2.0) ;-) Martin