RX / TX connectors from USB

[sebastian1986]

Hi,

I am trying to figure out a way to connect a second serial to my nano rp2040. Clearly the micro USB from the board needs to be connected to a rx/tx UART and converted via a onboard UART->USB converter. So I would like to make use of this fact.

I was wondering whether those two solder connections on the right, underneath the USB might be the rx/tx what I am looking for. Could only find the other solder connections in the documentation. Does anyone know?

Note: I do understand that going this route would require to remove the device from the Arduino whenever I want to do the USB communication / upload new code. Not ideal but I can live with it as I could not figure out how to add a Serial2 to my board. See other post:

Serial2 for nano rp2040 connect

Hi, i am trying to find a way how to connect two serial devices to my arduino. What i found so far is, that you use RX/TX with Serial1 on the nano rp2040. This works quite well. I did not find a way how to connect an additional serial device. Softwareserial clearly does not work on this board. This works on the nano 33 ble with the uart command: Help much appreciated! Thanks Sebastian

Thanks a lot!

[gilshultz]

Take a look at softwareserial, It may do what you need to do but it operates in simplex mode (tx or rx but not both concurrently). There modules that you can connect that will add serial ports as well. They are available in I2C, and SPI.

[sebastian1986]

Thanks for your answer. This is in fact exactly what i am looking for - was my first try Unfortunately it seems the SoftwareSerial.h library does not work on the nano rp2040 architecture. Do you know of any compatible library?
Thanks!

[Klaus_K]

@sebastian1986

Clearly the micro USB from the board needs to be connected to a rx/tx UART and converted via a onboard UART->USB converter.

The RP2040 is directly connected to the USB connector. It uses native USB. There is no UART->USB converter. Have a look into the schematic. The USB lines end in a red box and the signal D_P and D_N are connected to the D+ and D- pins at the top of the big yellow square (RP2040).

Schematic in store under DOCUMENTATION.

https://store.arduino.cc/nano-rp2040-connect

[Grumpy_Mike]

Note that when Arduino get round to supporting PIO you can use up to 8 pins for a UART TX or RX. These can be any pins.

This is done by programming these pins to be a state machine. Each state machine can have up to four bytes of FIFO.