Strongly recommend to use the nRF5 SDK drivers to access the peripheral instead of configuring it directly. Using drivers will also help you understand their usage and give you more confidence to configure then directly in future (if you need to)
The driver for I2S for example have init function you have nrfx_i2s_config where you can set the interrupt priority.the second argument will plugin your handler when the interrupt handler is called and When stopped, release all buffers, including these scheduled for the next transfer.
HAL is the hardware abstraction layer with bare minimal interface to the peripheral. The driver provides more abstract API and is built on top of HAL (i.e, the driver uses HAL API and builds more features on top of it)
Another question again ^^. Why pin 9&10 of nRF52832 cannot invert like GPIO, their description is "NFC antenna connection" and "General purpose I/O", the default usage of them is NFC? How to change its purpose to GPIO?
