HCI UART

RE: HCI UART

pstrueb — Wed, 09 Apr 2025 13:18:51 GMT

Im not a sure from your post, but the error is on the hci_uart side, right? I had the same issue and could fix it by
removing the following line:

		zephyr,bt-hci = &uart0;

I added it by mistake on the controller side in the overlay file, maybe you did so, too ?

the controller should have something like

zephyr,bt-c2h-uart = &uart0;

In the overlay instead.

Not sure if this is your issue, too but I thought it might be related

Patrick

RE: HCI UART

Christoffer Brask — Thu, 20 Mar 2025 08:21:52 GMT

Sigurd Any updates?

RE: HCI UART

Christoffer Brask — Mon, 17 Mar 2025 08:08:01 GMT

I have now tried this on both boards, but it still report the same error

<err> bt_hci_core: HCI driver open failed (-1)
Bluetooth init failed (err -1)

RE: HCI UART

Sigurd — Sun, 16 Mar 2025 13:40:22 GMT

Hi! You should place RX and CTS , and TX and RTS, in different groups. (RX and CTS group need bias-pull-up)

See this overlay:

	uart1_default: uart1_default {
		group1 {
			psels = <NRF_PSEL(UART_RX, 1, 1)>;
			        <NRF_PSEL(UART_CTS, 1, 4)>;
			bias-pull-up;
		};
		group2 {
			psels = <NRF_PSEL(UART_TX, 1, 2)>;
			        <NRF_PSEL(UART_RTS, 1, 3)>;
		};
	};

RE: HCI UART

Christoffer Brask — Fri, 14 Mar 2025 10:10:07 GMT

Hi Siguard,

Thanks so far

HCI HOST

RTS (1.03) -> CTS (P1.04)

TX (P1.02) -> RX (P1.01)

CTS (P1.04) -> RTS (P1.03)

RX (P1.01) -> TX (1.02)

I have tried adding the configs to the peripheral_hr prj.conf without any luck.

I also started playing with the reset but couldn't get bt_hci_transport_setup to be called. I assume it is called from h4_open?

From what I hear the reset shouldn't be entirely necessary, so maybe we shouldn't put to much focus on that?

RE: HCI UART

Sigurd — Thu, 13 Mar 2025 22:44:27 GMT

[quote user="Christoffer Brask"]I should have added that I have already tried that, changing the overlay file for the nRF52840 (hci_uart) to use UART1..[/quote]

So what pins are you using now?

[quote user=""]Do the nRF52840 DK (peripheral_hr) need to be able to reset the nRF52840 DK (hci_uart)?[/quote]

That would be more robust. We do that on the nRF9160-DK (where on-board nRF52840 can be used as a BLE Controller, and the BLE host can run on the nRF9160):

https://github.com/nrfconnect/sdk-zephyr/blob/main/boards/nordic/nrf9160dk/nrf52840_reset.c

https://github.com/nrfconnect/sdk-zephyr/blob/main/boards/nordic/nrf9160dk/nrf9160dk_nrf9160_common_0_14_0.dtsi#L20

https://github.com/nrfconnect/sdk-zephyr/blob/main/boards/nordic/nrf9160dk/dts/bindings/nordic%2Cnrf9160dk-nrf52840-reset.yaml

On the device that is the BLE host, set these:

CONFIG_BT=y
CONFIG_BT_HCI=y
CONFIG_BT_CTLR=n
CONFIG_BT_WAIT_NOP=y

[quote user=""]I assume I should not add the overlay-all-bt_ll_sw_split.conf when building the HCI UART sample?[/quote]

Correct, don't use overlay-all-bt_ll_sw_split.conf

RE: HCI UART

Christoffer Brask — Thu, 13 Mar 2025 13:39:29 GMT

I should have added that I have already tried that, changing the overlay file for the nRF52840 (hci_uart) to use UART1..

RE: HCI UART

Sigurd — Thu, 13 Mar 2025 13:35:06 GMT

Hi!

[quote user=""]

RTS (0.05) -> CTS (P1.04)

TX (P0.06) -> RX (P1.01)

CTS (P0.07) -> RTS (P1.03)

RX (P0.08) -> TX (1.02)

[/quote]

Pin 5,6,7,8 is connected to the interface MCU. I suggest using some different pins for HCI.

https://docs.nordicsemi.com/bundle/ug_nrf52840_dk/page/UG/dk/vir_com_port.html