"ASSERTION FAIL [err == 0] k_sem_take failed with err -11" when HCI is used with LP-UART

RE: "ASSERTION FAIL [err == 0] k_sem_take failed with err -11" when HCI is used with LP-UART

Carl Richard — Fri, 26 Mar 2021 11:04:11 GMT

Hi!

I've spent some time looking into this now and while I haven't found a fix yet, I think I've found the source of the issue. The host and controller must be synchronized somehow, this is, from what I can see, done by resetting the controller when the host is ready. On the nRF9160DK there is a dedicated reset line between the nRF52840 SoC and nRF9160 SiP, as well as firmware handling the hci setup. This is not implemented for the nRF52840DK.

I suggest that you study the nrf9160dk_nrf9160 and nrf9160dk_nrf52840 board definitions in the Zephyr, as well as the file nRF52840_reset.c, and see if you can reverse engineer the nRF9160DK setup to work for the two nRF52840 DKs. I'll have a look at this myself next week.

Bes regards,
Carl Richard

RE: "ASSERTION FAIL [err == 0] k_sem_take failed with err -11" when HCI is used with LP-UART

Anirudh Agarkhed — Wed, 24 Mar 2021 15:50:37 GMT

Yes, have used both 1000000 and 115200. When I was zipping the file, the config was set to 115200.

Regards,

Anirudh Agarkhed

RE: "ASSERTION FAIL [err == 0] k_sem_take failed with err -11" when HCI is used with LP-UART

Carl Richard — Wed, 24 Mar 2021 15:48:51 GMT

Understood! Then I will do some testing tomorrow and see if I can reproduce.

[quote user="Anirudh Agarkhed"]Just as an additional question, can HCI function over 2 Wire UART, and not mandate H4 which depends on 4 wire UART - CTS/RTS?[/quote]

It can. This is a restriction related to the hci_uart sample of Zephyr, and does not limit hci_lp_uart.

By the way, have you tried using 1000000 baud rate?

Best regards,
Carl Richard

RE: "ASSERTION FAIL [err == 0] k_sem_take failed with err -11" when HCI is used with LP-UART

Anirudh Agarkhed — Wed, 24 Mar 2021 15:29:25 GMT

Hello Carl,

Yes, that option is used, and also the example that you have mentioned is being used as a reference. Just as an additional question, can HCI function over 2 Wire UART, and not mandate H4 which depends on 4 wire UART - CTS/RTS?

Regards,

Anirudh Agarkhed

RE: "ASSERTION FAIL [err == 0] k_sem_take failed with err -11" when HCI is used with LP-UART

Carl Richard — Wed, 24 Mar 2021 15:02:20 GMT

Hi, Anirudh!

I'm looking into this. Have you made sure that the hci_host has the correct configuration, including CONFIG_BT_H4=y for enabling HCI over UART? You can look at the samples/nrf9160/lte_ble_gateway sample for reference.

Best regards,
Carl Richard