ChipKit Max32 / ArduinoMega 5V compatibility

[pistorinoj]

Sorry for the newbie question.

 

I am attempting to swap out an ArduinoMega 2560(R3) with the ChipKit Max 32.

One thing I am wondering about is how the fact that the Mega uses 5V while the Max 32 uses 3.3V will effect things.

In particular, I am using digital pins 22-31, e.g., to send control signals to stepper motor drivers and I understand that those drivers use 5V.

Likewise, I am using the 5V power pin to send a reference voltage to the drivers.

Finally, I am using analog pins A8-15 to sense 5V outputs from various sensors.

I see stuff saying that various pins on the Max 32 are 5V tolerant but I am not sure what that means with regard to my application.

Can I simply swap the Max 32 for the Mega or will the different operating voltages create an issue?

Thanks for any help,

James

[D@n]

The easiest answer is: Expect issues.

"5V tolerant" simply means that you won't permanently damage your part by connecting 5V to that pin.  Often you can still sense digital inputs, since a 3V circuit will test whether or not the input is greater than 1.5V (rather than 2.5V), but it's still not ideal.

You might find the PMod Logic Level Shifter to be valuable.  This will convert your 3V digital outputs to 5V, as well as converting 5V inputs to the 3Volts that your device is expecting.  You'll still need to get a 5V reference voltage from somewhere, however.  (USB perhaps?)

Hope this helps,

Dan