Jason implemented a frequency counter on an XC9572XL CPLD. It uses a 1Mhz clock to count the duration of the input signal pulse, and shows the output on a 6 digit display.
Initially he had to use additional 7400 logic ICs to convert BCD output from the CPLD to the 7-segment displays. With some tweaking of VHDL code he was able to squeeze it into the CPLD as well.
Get your own XC9572XL based CPLD dev board for $15 and start experimenting with programmable logic today.
Via the forum
Nice display, real vintage ;)
CPLD/FPGA development contest?