Using app_fifo_uart on SDK 9

[Ron]

I'm working with app_fifo_uart and I'm seeing that my event handler gets the event 'APP_UART_TX_EMPTY' repeatedly. Multiple times a second. Is there any reason for this? Can this be switched to only notify after tx buffer has sent all bytes rather than at all times?

[bjorn-spockeli]

The APP_UART_TX_EMPTY event is generated when the UART has completed transmission of all available data in the TX FIFO, please refer this page on the Nordic Infocenter. This means that after calling app_uart_put you will get an event (APP_UART_TX_EMPTY ), indicating that the byte has been successfully sent. The typical use case it the following:

1. Put byte in tx buffer of the UART using app_uart_put
2. Wait for the 'APP_UART_TX_EMPTY' event and put another byte in the UART tx buffer
3. Repeat untill all bytes have been sent.