drv_uart vs uart_app functions

Question

Hi, 
 Are the functions implemented in drv_uart and uart_app even related to each other? I noticed that uart_app implements only some simple functions. Can someone please explain to me the differences between these implementations? Can I freely call the functions from either of them? Are they any different from the blocking point of view? 
 -vala

Ole Bauck · Accepted Answer

App_uart or app_uart_fifo uses nrf_drv_uart. The FIFO (or buffer, not to be confused with the uart peripheral FIFO) in app_uart_fifo is implemented with the app_fifo module. 
 You should not used app_uart functions and nrf_drv_uart functions in the same project unless you know exactly what you are doing.