USB / UART Voltage and Power Limits & Other SBCs

UART
One of the FAQs reports the power on the UART is 5v. What is the current limitation?

What are the signal levels on the UART? The TX output is 3.3 v. Can a 5v signal be applied safely to the RX input or should it be limited to 3.3v?

USB
What are the current limits on the USB? Does the USB provide a serial connection? Is that how an Arduino communicates with the RVR?

SBC
I want to work with a single board computer (SBC) other than those documented which is why I’m asking the questions above. I’ll want to use the raw serial port commands. When will those be available? Can I help work with them now? I’m retired software guy who’s worked with embedded systems and robots for decades.

Greetings!

Q: One of the FAQs reports the power on the UART is 5v. What is the current limitation?

A: The UART power line does indeed provide 5V. The max current on that line is 2.1A.

Q: What are the signal levels on the UART? The TX output is 3.3 v. Can a 5v signal be applied safely to the RX input or should it be limited to 3.3v?

A: The UART signal lines only work at 3.3V. You should not apply a 5V voltage to them.

Q: What are the current limits on the USB? Does the USB provide a serial connection? Is that how an Arduino communicates with the RVR?

A: The USB provides up to 2.1A, but this power is shared between the USB connector and the 5V expansion port. The USB does provide a serial connection which is how we can communicate with Arduino Uno, and Micro:Bit. Not all versions of Arduino are supported though so make sure to check our website to see what you can use.

Q: I want to work with a single board computer (SBC) other than those documented which is why I’m asking the questions above. I’ll want to use the raw serial port commands. When will those be available? Can I help work with them now?

A: You should absolutely be able to use the serial port and send raw API commands to RVR. We are still currently working on the documentation, and will let you know as soon as we have something solid to share. In the meantime, you might be able to dig in deep in the SDKs that are available, and get an idea on how the packets are generated. This file shows how the LED commands are generated in one of our SDKs, and should help you get started.

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