How do I connect Vcc or signal to multifunctional pin

Hi all, I am working on this Arduino project which involves reading non-volatile memory. Since the design is to be compatible with memory chips of different sizes, I need to be able to configure the connections for each of these chips.

I have one pin in particular that for one chip is an address line (A13) and for another chip it is Vcc. Fr other pins, I can easily use a multiplexor to select the right signal that should go to the pin; however, I am wary about doing this for a Vccline sine this will need a higher current than the signal lines.

Specifically, I am looking at 32K x 8 and 2K x 8 chips. When placed in the socket, pin 26 (with respect to a 28 pin package) should be Vcc for the 2K chip or A13 for the 8K chip.

Any orientation is welcomed! Thank you, Saga

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clem57 over 6 years ago

I would suggest you build a logic table with all the examples you have. Then group common elements together. Take the most general cases and handle these first. Use the more specific ones or less general as hopefully one offs of the general case.As you go through this exercise, it becomes more obvious a simpler path to the design you will need.
Just my thoughts,
Clem
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shabaz over 6 years ago

Also, strongly suggest you read and experiment with transistors (BJT and MOSFETs), because sometimes the solutions with them are easy, for controlling power, which is what you're essentially trying to do. Schottky diodes can sometimes be helpful too, for reasons that can become clear once you're trying to connect one or more signals (or power sources) in an 'or' gate type solution.
If you need help with the experimentation, simulation is a good way forward too, e.g. falstad simulator: https://www.falstad.com/circuit/
Example simulations (there are some with transistors there too, that you could play with or edit): https://www.falstad.com/circuit/e-index.html
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clem57 over 6 years ago in reply to shabaz

Thanks for the Links shabaz . And it works from a browser too.
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SGarciaV over 6 years ago

Thank you both for your replies. I appreciate the links. The simulator is way cool!

BB-Sphere, thanks for the helpful advice. In fact, this is what I did and managed to simplify most of the lines. I ended up with only one line needing to switch between a signal line and Vcc.

Best regard to both, Sgarcia
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clem57 over 6 years ago in reply to SGarciaV

Glad to help you. Could you please mark answer correct for others that may follow.
Happy playing!
Clem
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