Using UART on donfle with an external power supply of 3.3V

[sotillo2409]

Hi everybody,

I am experience a strange thing with dongle.

With a modified Uart example, i modified uart0 pinout to pins rx->1.13 and tx->1.15. I think thats pins are free and available to be uart0.

Later and following the guide, i cut sb2 and solder sb1 to alimentate throught vdd out with regulated 3.3v of another micro.

When i transmit data throught the UART the dongle doesn't able to receive it, and doesn't send that data throught BLE, i don't know why.

I try testing sending data without using the UART and it work, so there are any factor that doesn't able to the device read data in.

If I supply the device throught usb the uart work properly.

[Simonr]

Hi

If you check out the pin assignments in the nRF52840 PS, you'll see that P1.13 and P1.15 are recommended to only run as Standard drive, Low freq. I/Os. This is because they're located close to the radio, and may interfere with the radio performance when running at higher frequencies while the radio is active, which I'm guessing why you don't see the data over BLE at all.

Try using pins that do not have this recommended usage note instead, and I think you should be able to see that the device is able to receive and transmit data over BLE while the UART is active.

Best regards,

Simon

[sotillo2409]

Ok maybe that is, when arribe new dongles to my house, i burned 2 because of solder and desolder, but is okay i will try, now is working with 5v and the regulator, so enough at the momment.

Thank you for the support Simonr.