How many UART ports does the Arduino UNO R4 have?
I saw in a website (given below) saying that the Arduino has two UART ports, one in the USB and one in 0 and 1 pins. But in the Arduino website, it shows only one.
https://dronebotworkshop.com/arduino-uno-r4-minima-wifi/
Also if it does have two UART ports, is it only in one of the variants or both the variants (Minima and WiFi) have them?
15 Replies
Unknown User•13mo ago
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as many pins as it the microconroller has! Software UART can emulate hardware UART (:
Unknown User•13mo ago
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The Uno R4 minimal has not ESP32S3, it has only the Renesas chip on it directly
Renesas R7FA4M1AB.
Unknown User•13mo ago
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well then @juan gotta tell us what board they are actually talking about-
well i think both
see the full website
the Arduino core exposes very different for the Minima and WiFi boards
the chip has way more capabilities than the ArduinoCore-Renesas exposes.. the Uno R4 Wifi is declared to have 3 serials. But two are used internally to communicate with the ESP32S3, one for WiFi-data and one for the sarial monitor. Then, the UART on D0/D1 still have a free UART. The ESP32S3 impelments a USB-CDC bridge in this case.
the Uno R4 minima is directly connected to the USB port an can open a USB CDC
Serial . Alongside the hardware UART at D0/D1.
in the Arduino IDE, that is accessed as Serial (USB CDC / Serial monitor) and Serial1 (hardware UART on D0/D1)
again, the chip has more capabilities than the Arduino IDE / Core exposes.E.g., the I2C pins can actually be serial pins, too.
this is the minima, right?
couldnt find this in the arduino website
let me search that
found it
this is the r4 minima cheat sheet
however it should be clearly mentioned in the datasheet and in the store page
thanks for all your efforts
conclusion: both arduino uno r4 minima and wifi have two uart ports. one is connected to the usb-c connector and one is connected to pins 0 and 1, and the latter is addressable by
Serial1.USB-cdc is not uart, technically. It is a serial implementation done via the USB peripheral. Uart is Uart.
sorry mb