Do threads yield during synchronous operations?

[talha]

I have a very simple and general question about Zephyr and nRF Connect SDK. When I am running a thread with high priority that uses I2C and call a blocking synchronous function, i.e. i2c_write_dt or i2c_burst_read_dt, does the thread yield so that another thread runs while this one is blocked? Is there a documentation that I can read about this?

[Amanda Hsieh]

Hi, 

When a thread calls a blocking synchronous function, such as i2c_write_dt or i2c_burst_read_dt, the thread will indeed yield and another thread can run while the first one is blocked. This is because these high-level calls accessed through device-specific APIs are usually intended as synchronous and thus, they should be blocked. See Thread life cycle. 

You can take a look at the nRF Connect SDK Fundamentals course and nRF Connect SDK Intermediate course which provides a comprehensive overview of these topics, including hands-on exercises to practice creating threads, thread yielding and sleeping, and offloading work to a workqueue.

Regards,
Amanda H.