I got to thinking that there must be a simpler way to make a clock source… https://eater.net/8bit/clock and I realized that using anATTINY85 based board seemed a bit of non-retro silliness after a while… So I looked again for a legacy IC-based solution with a lower chip count than 3 LM555s and a few additonal GLUE LOGIC ICs. Keep in mind, this was not because I have a problem with the LM555 clock source from Ben, as this was just an ‘experiment’. After a while of searching through my parts, I found the CD4047 IC. So, here is what I came up with. The best results for me came from using the `Q out pin... but bothe ‘Q’ and ‘/Q’ are available in addition to the OSCILLATOR pin.
I did get my PCBs… so here is Rev1 with a switch bodge as I need to add a capacitor across the switch for reliable presses. So this is what the CPU clock circuit becomes. Revision 2 will add a Halt feature… and O only needed 1 more resistor.
