req_pin_idle() in uart_nrf_sw_lpuart.c

[td-pradecki]

Hi!
I am developing application for nrf52840 on nrf connect sdk 2.9.0.
I am using mcuboot with serial transport as a bootloader. In bootloader I am using uart with hwfc and in application I am using lpuart for hci communication.

The same pin is used for hwfc rts and for lpuart req pin.

I was experiencing strange behaviour of req pin when hwfc was enabled in bootloader.

I managed to fix the problem by changing:

static void req_pin_idle(struct lpuart_data *data)
{
	nrf_gpio_cfg(data->req_pin,
		     NRF_GPIO_PIN_DIR_OUTPUT,
		     NRF_GPIO_PIN_INPUT_DISCONNECT,
		     NRF_GPIO_PIN_NOPULL,
		     NRF_GPIO_PIN_S0S1,
		     NRF_GPIO_PIN_NOSENSE);
}

from uart_nrf_sw_lpuart.c to:

static void req_pin_idle(struct lpuart_data *data)
{
	nrf_gpio_cfg(data->req_pin,
		     NRF_GPIO_PIN_DIR_OUTPUT,
		     NRF_GPIO_PIN_INPUT_DISCONNECT,
		     NRF_GPIO_PIN_NOPULL,
		     NRF_GPIO_PIN_S0S1,
		     NRF_GPIO_PIN_NOSENSE);
	nrf_gpio_pin_clear(data->req_pin);
}

According to lpuart documentation, this is correct logic. I think it is a bug and should be passed to ncs developers.

Kind regards,
Piotr Radecki

[dejans]

Hi,

Thank you for reporting this potential issue.

What do you refer to as hwfc? How did you enable it in the bootloader?

I was experiencing strange behaviour of req pin when hwfc was enabled in bootloader.

Can you elaborate on the problem? What was strange behavior about? Do you have any logs to share?

Best regards,
Dejan