Units of measure, binary versions: K(ilobyte) = 2^10 M(egabyte) = 1024 * K = 2^20 G(igabyte) = 1024 * M = 2^30 Units of measure, decimal versions: K(ilo) = 10^3 (1,000) M(ega) = 10^6 (1,000,000) micro (u with a tail) = 10^(-6) nano = 10^(-9) Appropriate measures for counting cyles and times. The 68HC811 runs as 2MHz, i.e., 2 million cycles per second. Hz = Hertz, a measure of cycles/second. 2 * 10^6 cycles/second 1/(2*10^6) seconds/cycle = (1/2) * 10^(-6) seconds/cycle. So each cycle lasts .5 microsecond. ==============================