Hello
The Uart is the Driver, the uart_adapter is an "higher level" componant.
Then the Uart_Adapter use (and need) the Uart driver.
If I use only the Uart Driver, I should make some management which are already done by the uart_adapter.
I try to recreate a dummy project, just with adding uart and uart_adapter.
Then the UART2_FLEXIO_IRQHandler is existing into startupt_mkl17z644.c file, which call
UART2_FLEXIO_DriverIRQHandler function => IntDefaultHandler => while(1)
Like this function has attribut "Weak" if declared in other place, this declaration not used.
But like UART2_FLEXIO_IRQHandler is not declared, but UART2_IRQHandler into uart_adapter.c, when interrupt occurs, it is the IntDefaultHandler which is called instead of UART2_IRQHandler ...