my nrf52833 uart tx pin is low level when it is idle.

RE: my nrf52833 uart tx pin is low level when it is idle.

Einar Thorsrud — Wed, 19 Feb 2025 14:37:30 GMT

Hi,

The nRF UARTE periphearl does not support inverse polarity, so this is not it. Does the other device have pull-up enabled on the Rx pin? If so, perhaps it woud make sense to enable pull-up on the Tx pin (though unconventional). That is also what we do on our development kits by default, see here.

RE: my nrf52833 uart tx pin is low level when it is idle.

nick yong — Tue, 18 Feb 2025 13:51:37 GMT

NRF_UART0->PSEL.RXD = pinrx;

NRF_UART0->PSEL.TXD = pintx;

NRF_UART0->BAUDRATE = DEF_uart_baud; // value for 115200

&pinctrl {

uart0_default: uart0_default {

group1 {

psels = <NRF_PSEL(UART_TX, 1, 1)>,

<NRF_PSEL(UART_RX, 0, 4)>;

};

uart0_sleep: uart0_sleep {

group1 {

psels = <NRF_PSEL(UART_TX, 1, 1)>,

<NRF_PSEL(UART_RX, 0, 4)>;

};

is there some register to inverse the uart pin logic? up to now, I cannot find the configuration about polarity。

the uart register would contol all the behavior? which register would control the logic level. thanks.

RE: my nrf52833 uart tx pin is low level when it is idle.

Einar Thorsrud — Tue, 18 Feb 2025 13:02:12 GMT

Hi,

I am not immediately able to explain that. Can you share/show how you have configurd and use the UART, both in code/configuration and hardware?

RE: my nrf52833 uart tx pin is low level when it is idle.

nick yong — Tue, 18 Feb 2025 12:25:39 GMT