My application involved exactly that : 'a circular buffer',so the E2prom was out because of 'write time'.What I worried about using data space was being confronted with read/modify/write complications within the program itself.I would have to have something within the program that monitored the space I allocated for this buffer.I think this may be a case of short sightedness in laying out my circuit(more like wishful thinking in retrospect).I am about to re-design the board and am considering external hardware so as to have plenty of 'ceiling' for a substantial buffer.Some SRAM comes to mind but I was looking at some E2PROM that seems to have a much improved write times (compared to the on-chip E2PROM)that seem to come within the timing parameters. -Keith