Serial communication between Arduino Uno R4 and R3

[keymind]

I was working on a project using Arduino Uno R3. However, when I upgraded to Arduino Uno R4 wifi, the servomotor vibrates and doesn't work. Unfortunately, I haven't been using Arduino for long, so I don't know how to modify the code to work. So I'm trying to get the existing R3 to work with serial communication, but can it work with the code used for serial communication between the existing R3-R3 or R4-R4?

[UKHeliBob]

Welcome to the forum

The Serial interface on the R4 uses the USB connection to the PC for the Serial monitor and to upload code

If you want to use pins 0 and 1 on the R4 then use the Serial1 object

[mancera1979]

R4 has different IO pin specs than R3. Namely, output current limitations.

Check out https://docs.arduino.cc/resources/datasheets/ABX00087-datasheet.pdf, #11.3

and provide a connection diagram showing the board, servo, power supplies and whatever else is there

[ZX80]

Trouble with Servos on R4 Wifi

Hi! Just got my r4 wifi today, and I'm having trouble getting it to work with servos. As best I can tell, the PWM output on the pin is updated much less frequently than it's supposed to be, resulting in a ticking like behavior on the servo. To eliminate variables right out the door, I am properly powering the servo externally, and have a shared reference ground with the servo power supply and the MCU. As well, even the basic example "Servo Sweep" for me on my R4 wifi exhibits this behavior. Usi…

[jremington]

@keymind

However, when I upgraded to Arduino Uno R4 wifi, the servomotor vibrates and doesn't work.

Be sure to power the servo independently, and connect the grounds.

[keymind]

I double-checked and found that I didn't connect the power properly. It works perfectly now. Thanks everyone!