Sharing pins on 2 pro minis used alternately

Hello,

I want to use 2 Arduino Pro Mini 328 on the same setup. Both will run different code and will have some pins interconnected to a 4050 IC and some buttons. I want to switch between the 2 Arduino boards with a DPDT switch that will switch both VCC and GND. The Arduinos will never run at the same time.

Will this cause any issues? For example Pin 10, of both Arduinos will be connected to the same 4050 pin so this means that there will be a physical connection between pin 10 of the 2 Arduinos. Pin 6 from one Arduino and pin 8 from the second Arduino will be connected to the same button. Same for analog pins. Will the fact that an Arduino that has no VCC and GND connection but other pins connected to the second Arduino disrupt the way the second Arduino works?

If you are asking why, it's because all the code pieces will not fit onto one pro mini 328 and I don't have the funds to buy a Mega. Also I have the switch and everything I need to connect them so I don't have to wait for new parts or spend money on them.

It's possible to power an entire µC from its IO pins!

I'd use a big enough connector (shield...) for external circuitry, so that the controller can be swapped on the fly.

it's because all the code pieces will not fit onto one pro mini 328

How close to fitting is the combined code ? What steps have you taken to minimise memory use ?

arduini1980:
Will this cause any issues? For example Pin 10, of both Arduinos will be connected to the same 4050 pin so this means that there will be a physical connection between pin 10 of the 2 Arduinos.

Rather than switch off one of the Arduinos use the switch to signal a change of mode so that the unwanted Arduino sets all its I/O pins to INPUT.

...R

Hey! I smell XY Problem! :astonished:

Badly. Little point offering nice things until OP comes out of hole.

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html .

Why do you need two arduino?
Why can't one Arduino run both codes?

What is the application?

Can you draw us a basic diagram of how you want to connect your two Arduinos together.

Can you tell us your electronics, programming, arduino, hardware experience?

Thanks.. Tom.. :slight_smile: