Hi Gil,

its easy to build a frequency counter up to 100MHz with the 8051.

I use 3 SN74S90 as prescaler. With using the R0 and R9 inputs you can select divide by 10 or feed through. So with 2 lines you can select a prescaler of 1, 10, 100 or 1000 and the 8051 can count the output.


Peter