How to configure the parity, stop_bits, data_bits, flow_ctrl parameters of the UART in the xx.overlay file in NCS？

[Jim]

I want to know how to configure parity, stop_bits, data_bits, flow_ctrl parameters in UART in the xx.overlay file.

Although these parameters can be configured through the uart_configure interface, I prefer to configure them through overlay files or other methods instead of modifying the code.

[Simon]

In this answer I assume you're setting compatible="nordic,nrf-uarte" in the uart node instance

• To configure parity, use the configuration CONFIG_UART_<instance>_NRF_PARITY_BIT
  • E.g. if you set  CONFIG_UART_0_NRF_PARITY_BIT=y, an even parity bit will be used for UART0, otherwise, no parity will be used
  • It does not seem like setting the field parity to "none", "odd" or "even" will have any effect, since the driver uart_nrfx_uarte.c does not get it from the device tree
• To enable RTS/CTS flow control, add the field hw-flow-control to your UART instance. Like it's done in the serial_lte model example
  • uart_nrfx_uarte.c will then use the macro UARTE_PROP to get it from the devicetree/overlay
  • If you want to set it to e.g. DTR/DSR, you have to use the uart_configure() function
• To set the baudrate, set the field current-speed to any of these values
  • uart_nrfx_uarte.c will then use the macro UARTE_PROP to get it from the devicetree/overlay
• To set the data bits and stop bits, you have to use the uart_configure() function, like it's done in zephyr/subsys/mgmt/osdp/src/osdp.c
  • The uart_nrfx_uarte.c driver will set the data bits and the stop bits to some default values 8 and 1, so it will not have any effect setting this in the device tree. However, I could not find any fields for these properties in any bindings files regardless.

Best regards,

Simon

[Jim]

thank you for your reply.