Use Sparkfun Servo pHat v2 UART to control an Arduino

Robotics
1

Hi team,

I would like to introduce a communication path between my Raspberry Pi Zero W using a Sparkfun Servo pHat v2 and an Arduino clone (5V Adafruit Trinket Pro). I’ve already tried using the actual servo pins to control digital pins on the Trinket, which works fine but only in isolation (without actually using the servos at the same time). I can detail how I’m doing this if anyone is interested. :slight_smile:

I’m now forced to try to find a different way. So I am thinking of using the UART from the pHat since it already works at 5V as opposed to the 3.3V of the Qwiic system.

My question to the team is: is it safe to connect the RX and TX pins from the pHat to the TX and RX pins on the 5V Trinket? And if this is the case, I need to handle the transmission myself through controlling the Raspberry Pi UART right? I’ve looked into the Sparkfun Servo pHat library code and there is no specific code for the UART communication.

Thank you!

PS: If you have any/other suggestions to communicate (I’m only interested in one-way RPi → Trinket) between the two components, please let me know.

2

Hi team,

Is it possible to get a response on this one: is it safe to connect the RX and TX pins from the pHat to the TX and RX pins on a 5V Adafruit Trinket?

Thanks!

3

RX and TX on this product are just go to the Pi and don’t actually control anything on the pHAT. You can use them to communicate serially between the Pi and an Arduino though. Since the Pi is a 3.3 volt device, you’d need to connect a logic level converter between your 5 volt Arduino and the pHAT to avoid damaging your Pi.

If you wanted to use the pHAT to control servos with an Arduino, that could be done through Qwiic (I2C) though.

4

So the RX and TX provided for the RVR has a 3.3 voltage? It’s specified on the board as 5V.

5

There’s a 5 volt pin on the serial header, but RX and TX operate at 3.3 volts.

https://sdk.sphero.com/docs/faqs/rvr_faq/