We’re considering buying Link.One which contains the BG77 module in the IO slot. The datasheet of BG77 indicates that UART is bound on pins 33 and 34, which is UART1.
We’d like to connect a UART sensor to Link.One, is it possible? Is the other UART (UART0) available on Link.One? It seems that UART0 is useable only in the IO slot which one of your employees confirms
If that’s true, we won’t be able to use Link.One in our project, as our sensor requires a UART connection.
Welcome to the forum @lukasp
Sadly it will not work. The UART exposed on the base board on pin header J10 is the same UART used by the RAK5860 cellular module.
As an alternative you could look into our new Blues.ONE. This cellular module is using I2C and you could use the UART on the Base Board header.
Thanks for the quick response. I think we’ll consider using Dual IO Board instead, Blues.ONE is too expensive.
By the way, is using slots A or D also out of the question? Do they also only have UART1?
Slot A and D are using the same UART as well, that is not a solution for you.
If you take the Dual-IO Base Board, you can access the second UART through the RAK13002
Reviving an old thread in case anyone else is interested: you can emulate UART on a GPIO pin. We only need to receive from a sensor, so we’re using IO2 on RAK19007 to emulate UART RX. For example on Arduino you can use the SoftwareSerial library, however our solution is written in Rust and we are not using Arduino. Making it work from scratch doesn’t seem to be that complicated.
Software emulation of UART has its limitations but it looks like in our case — infrequent sensor inputs — it will work. We will do more field testing but I’m hopeful.
Found an even better solution, you can use any GPIO port as UART on nrf52840: nrf52 UART pins - Nordic Q&A - Nordic DevZone - Nordic DevZone
We didn’t have to deal with PSEL, it was handled by the library we’re using, so the full diff was just 3 bytes to change the pin number for UART RX. No need to emulate UART in software.