2 articles were written in April 2012:

The original plan for my first real CPLD project was to build a NCO (numerically controlled oscillator), which in turn should be used to build a wave generator. But shortly after I happened to find a SPG8640BN chip in my parts bin. This nice chip, which is unfortunately not produced anymore, produces a square wave output from 1 MHz down to 1/120th Hz, in 57 steps. I build a small generator with it, with 16 frequency steps between 83.3 Hz and 100 kHz. So there was no immediate need for a NCO (especially since I found a MAX038 beneath it), and I decided to build a frequency meter instead.