NRF CLI Thread Safe?

[Dave_couling]

In SDK 15.2 is the nrf_cli module completely thread safe?  I was thinking of developing a wrapper to use the CLI module for both application logging as well as a general CLI interface. Since I'm using a freeRTOS arhcitecture I didn't know my wrapper have to make it threadsafe or if the nrf_cli was already developed this way?   I know in nrf_log the deferred setting makes logging thread safe, but I don't see the same option for the CLI module.  

Thanks guys (and Happy New Year)

-DC

[Jakub Rzeszutko]

Basically it is not thread safe. However you can safely use it with RTOS under following conditions:

1. CLI commands will be not executed from from multiple contexts (to avoid executing commands at the same time).

2. nrf_cli_fprintf function will be used only inside command handler. If you wish to print something on the screen from different context you can use Logger module with CLI backend.

[Dave_couling]

1. Understood, I'll wrap this into its own thread with a Semaphore

2. The usage of the term backend is quite confusing.  I use RTT backend on my CLI (may change to UART depending on the application).  So as I understand, there is a setting which hooked the Logging into the CLI as the backend which then uses whatever backend is configured for the CLI?

[Jakub Rzeszutko]

You can create as many CLI backends as possible: BT, UART0/UARTE0, UARTE1 (nrf52840), RTT or USB.

Each backend is independant and you can use them "at the same time". Each CLI backend can be at the same time a Logger backend. What is more you can configure each backend to show different log levels and it can be changed at runtime.

So I think the answer for your question is simply: yes.

[Dave_couling]

I thought you weren't allowed to use a backend for both logging and cli.  I guess this is where you'd set the #define NRF_CLI_LOG_BACKEND 1 ?   To be able to use Logging -> thur CLI -> to whatever backend is configured for CLI (e.g. RTT or UART)?

[Jakub Rzeszutko]

You are allowed to use a backend for both. Example can be found in peripherals\cli

[Dave_couling]

Wanted to re-address this issue.  I've been finding with extensive testing that the CLI module will randomly assert.  If occurs on line 270 of nrfx_uarte.c results from a NULL pointer passed for p_data.  This seems to occur randomly, whether the Softdevice/BLE Thread is running or not.  The Thread trace shows the following: