Help with cd4017 control switching electronic rotary knob

[karaandnick]

I am working on a circuit that will control the selections on a arcade pcb. Basically I have a 6-in-1 arcade pcb switcher (a board that holds 6 individual jamma boards), when you press a button on a wireless remote it switches to each of the boards. The wireless interface to the pcb board is very simple and has already been figured out by someone else. The main PCB has a wireless daughter board attached that connects via 6 pins, +5, and negative. Each of the 6 pins controls which of the boards is active by going high. Currently people are putting a rotary switch in place of the wireless board on the main board. I want to do something different so that the machine looks totally stock. I want to make it where you push both "start" buttons at the same time and the game switches. I currently have a cd4017 decade counter wired up as shown in the figure below. My question is how do I control the chip with the two "start" buttons? I can't wire + on one button and neg on the other or they will ground when you push each of them individually. I have been trying to figure out how to use a 555 to control the 4017 but am stuck. Also I am not married to the cd4017 so if there is a better way please let me know. I am very electronics illiterate but can read circuit diagrams. Basically I need a digital rotary switch. Also I would like it to remember and stay on the selected setting when powered down and then back up.

I currently have the circuit built and attached to the board which switches just fine, I just cannot control the switching by pressing both "start" buttons at the same time. Both "start" switches are wired high and low sharing a common ground, if this helps. Also if it helps the "start" buttons are 3 terminal, +5, "-", and Normally closed "-".
Any help would be greatly appreciated and thanks in advance.

 

[panic mode]

if i recall, inputs are active low (when switch connects to 0VDC). so just make simple inverted AND gate using two transistors instead of switch. connect bases through resistors to your buttons.
when buttons are open ("high") transistors are off. only when both buttons are pressed, both transistors conduct. and provide pulse to your circuit. btw there should be some signal shaping/debouncing. i would at least add capacitor...

 

[Mike odom]

the problem with data retention is that you'd have to keep power on the 4017 when game power is removed. Since it's CMOS, not a big deal, AA would work (cmos keeps memory down to .5V), however, you'd also be powering anything that the chip is sourcing, like what's on its output line.

 

[mbarazeen]

why don't you use the enable input of 4017 to do the job with start button?

Edit: you can use NO contact of the start button that is not in use as i understand, to enable 4017.

 

[Mike odom]

why don't you use the enable input of 4017 to do the job with start button?

Edit: you can use NO contact of the start button that is not in use as i understand, to enable 4017.

but that doesn't get it to count up

 

[alec_t]

Both "start" switches are wired high and low sharing a common ground, if this helps. Also if it helps the "start" buttons are 3 terminal, +5, "-", and Normally closed "-".

If I understand you correctly each switch output is normally at 0V and goes to +5V when the switch is pressed? If so, all you may need is two diodes and a 10k (or up to ~ 100k) resistor wired as a diode NOR gate. Connect one switch output to the cathode of one diode. Connect the other switch output to the cathode of the other diode. Connect both diode anodes to one end of the resistor and to the clock input pin of the 4017. Connect the other resistor end to +5V.
If switch debouncing is required a more elaborate circuit would be needed.