Thank you!
I hope that doesn’t add too many parts (and therefore cost); I could not find a way to chain them without additional logic gates.
There is just one connection between Q9 output and clock inhibit: when they connected, counter stops counting and wait for external reset. So you can create a loop of couters by connecting one last step output to next reset input
And this needs an inverter somewhere, because the step outputs are high-active and the reset input is the same. Which works great for resetting the counter early, but if we want to prevent the second module from counting before the first one has reached its last step, we must keep the reset input (of the second module) H, until the last step (of the first module) activates.
Having tested it on a breadboard with two chips and a lot of LEDs: I must correct myself, it works without additional components (inverters or logic gates), although I get the reset signal for the next chip from the next-to-last state, not from the "stop“ state.
This solution has one disadvantage, which does not matter for a modular synth but makes it unusable almost everywhere else: it can, after power-on, start in an “illegal” state, e.g. all chained modules running in sync, instead of only one running at the same time. That is easily cleared up by switching one module into independent mode for a moment.
The datasheet for the old 4017 (CD4017B) has a circuit example for chaining (it is called cascading there) using an AND gate to block the clock to the next chip before the final state is reached. They AND gate could be built from a diode and a resistor (no extra chip needed), and it gives one more usable output for the whole chain (and well-defined reset behaviour), but it would need more connections between adjacent modules, making it less practical for our application (we want easy-to-use modules with few chances for wiring mistakes).
Yep, I also wanted to say there is no need to add some inverters. We already made this technique for sequencer module.
Can you share your schematic?
This is the one that works, it gives me 16 step outputs (I left out power connections and the LEDs):
The Reset-timing is tricky: by the time one chip releases reset for the other chip, the clock flank that triggered the release is gone. So the next chip will wait for the next clock pulse before it does anything with its freedom.
That is why A:Q9—>inverter—>B:Reset didn’t work properly, and that is why I use Q7 to reset the next chip.
