RE: LPUART first message fails

Kazi Afroza Sultana — Fri, 31 Jan 2025 07:51:25 GMT

Hello,

Based on the zephyr version print, it seems that you are using ncs v2.4.x.

https://github.com/nrfconnect/sdk-nrf/blob/v2.4.4/west.yml#L62

This could be an issue that we have fixed in newer versions.

Have you tried latest version of NCS?

RE: LPUART first message fails

Miguel Ferreira — Tue, 21 Jan 2025 17:42:54 GMT

Hi,

Meanwhile I found a "dirty" solution to this. But first going to your question. The LPUART configs are being set by using uart_configure function.

struct uart_config uart_cfg = {
/* data */
.baudrate = 115200,
.parity = UART_CFG_PARITY_NONE,
.stop_bits = UART_CFG_STOP_BITS_1,
.data_bits = UART_CFG_DATA_BITS_8,
.flow_ctrl = UART_CFG_FLOW_CTRL_NONE};

Device Tree:

&uart1 {
/* UART to NRF91 */
compatible = "nordic,nrf-uarte";
status = "okay";
current-speed = <115200>;
pinctrl-0 = <&uart1_default>;
pinctrl-1 = <&uart1_sleep>;
pinctrl-names = "default", "sleep";
lpuart: nrf-sw-lpuart {
compatible = "nordic,nrf-sw-lpuart";
status = "okay";
req-pin = <6>;
rdy-pin = <12>;
};
};

&gpiote {
interrupts = <6 NRF_DEFAULT_IRQ_PRIORITY>;
};

A similar config applies to the NRF9160 side.
Packet size and message size are ok.

Regarding the solution I currently found, the change introduced is basically on the NRF52840 side. So, after sending a message I will wait 25 ms and force the RDY and REQ pins. By forcing I mean, call the rdy_pin_blink and req_pin_idle from the LPUART driver. By doing this the system behaves as expected - I receive the whole payload and the first message is sent. Maybe what Im seeing is a timing issue regarding the REQ and RDY lines. Do you have any idea what could cause this ?

Thank you!

RE: LPUART first message fails

Kazi Afroza Sultana — Tue, 21 Jan 2025 16:36:53 GMT

Hello,

How have you set the LPUART configurations? If the packet size and buffer size are accordance to the message size?