> Why doe's almost everybody use the 68hc11 ,. 68hc16 microcontroller,. > and almost nobody use MCS51 compatible(8031,.32,.51.,52) micro ? Some Bosch Motronic use 8051 variants. Why 68HC11? Because it's easier to program. I think the 8051 FAQ describes the 8051 as bizarre... I certainly wouldn't choose it. Orin.