Firstly thank you for the support. I have purchased a SparkFun LTE GNSS Breakout - SARA-R5 board with the idea to send a text message from an esp32. I have successfully powered up the Sara board with a 5v dc dedicated power source and the lights are on. The Sara board powers on and off, power button works with the power light going off/on. My concern and ask for support is how to communicate with the board. I have the RX and TX connected but no serial response or output in Arduino. I have tried swapping the RX/TX and still no output. I would like to start with simple test to get SARA board information but even using the examples no success. Any help would be great. Also I am new so please be patient with me. David.
By default, those pins will be passed through the USBs and need to be cut so you can isolate and interact with them. More information in the hook-up guide:
That’s fine, I was asking whether you had cut the tracers beneath RXD0 and TXD1 to open the lines. Because otherwise those pins are closed in their default state.
Thank you for the help, is there a document which describes this so I can do some reading. I will cut the two joins for RX and TX and come back with results.
Only the TX and RX Jumpers need to be cut for it to work. Would you be able to upload a photo of your board and how you interacting with it? It would make it easier to offer support.
Hi Jane, apologies for the delay in my reply. I have attached photos of my setup. I have 5V and GND from the ESP32 Micro to the Sara board. The Sara board power up with lights on. I have the RX and TX going to the right pins on the ESP32 board. I have cut TXD1, RXD0, RTS1, DTR TXD21.
If the RX and TX are correctly connected than their corresponding LEDs should be lighting up on the side. I would also recommend tidying up the solder on the TXD1 which doesn’t look quite as well connected as it’s neighbour.
Also, could you please confirm the make of your microcontroller? It would be useful to triple check the pin outs for the board.
Hi David
The TX and RX LEDs will only light up when there is Data traffic on the circuit. Even then it will only be brief flashes corresponding to the HIGHs (or LOWs depending on actual circuitry). Similar to the TX and RX LEDs on an Arduino when communicating such as loading a sketch or similar.
Cheers Bob
Bob is right, hence why I asked you to tell us your microcontroller’s name so I can confirm pin out has been configured correctly. In addition, could you upload the code you are using to flash the SARA? With both of those bits of information, we can determine if the serial communication has been set up correctly on the microcontroller.
