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

Jim — Tue, 02 Nov 2021 06:18:23 GMT

thank you for your reply.

Simon — Thu, 28 Oct 2021 12:49:20 GMT

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