nRF52833-DK uart communication with nRF52840-DK

Hi,

I use two nRF52833-DK boards for uart communication (both using pin p0.06 for TX and p0.08 for RX),
with their TX and RX and GND pins connected to each other, and perform a UART transmission test:

One board is responsible for sending UART data, and the other board is responsible for receiving the data, the transmission works without any issues.

However, when I replace the receiving nRF52833-DK board with an nRF52840-DK board,
I find that when the UART RX pin on the nRF52840-DK receives UART data from the nRF52833-DK and the data is bit1,
the voltage level is about 3V, which is similar to the nRF52833-DK.
But when the data is bit0, the voltage level is raised to around 1.6V and cannot drop close to 0V, causing transmission problems.

Does the nRF52840-DK require any additional configuration to work with UART communication from the nRF52833-DK?
All DK boards are powered by VDD.

Parents Reply Children
  • 1. 


    2.
     yes,
     If I disconnect the nRF52833 from the nRF52840, the signal go all the way down to almost 0v for a logical 0.


    Btw,
    I programed the smp serve example code on the receive end.
    I implemented the smp client on the transmit end.
    Two nRF52833-DK work as expected and I don't have any other hardware setup.
    If I replaced the receive end from nRF52833 to nRF52840, I encountered the uart voltage level issue.

    I want to know if any special hardware settings are required for UART communication between an nRF52840-DK and an nRF52833-DK ??

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