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interface serial rx/tx to 3.3 volt uP

Posted: Mon Jun 19, 2017 7:07 pm
by ChrisA
I want to connect the roboclaw serial pins to a 3.3 volt micro controller. I know to scale the TX pin with a voltage divider so as not to damage the uP RX pin.

Question. Is the 0 to 3.3 volt signal from the uP TX pin enough to drive the Roboclaw RX pin? or do I need to translate this up 5 volts? How does the RX pin work? Is it just a high value pull up?

I know I can simply experiment but I need to know if this use is in-spec and going to be reliable

Re: interface serial rx/tx to 3.3 volt uP

Posted: Tue Jun 20, 2017 9:17 pm
by Basicmicro Support
Scaling the voltages is unnecessary. The Roboclaw is a 5v tolerant device but the underlying system is 3.3v already. You can directly connect the signal lines from the Roboclaw to a 3.3v microprocessor.