UART and Tx interrupts | Cypress Semiconductor
UART and Tx interrupts
I'm using a UART, full duplex, 19200, 8,N,1 RS485 enable hard control. I've enable interrupts for Rx and Tx. Rx int works perfectly, but I've problem with Tx ints (and it's possible I don't understand something). Buffer is 4 bytes, so no internal ints are available. If I've marked trigger ints on "fifo empty" and/or "fifo not full" no ints are generated. The only way to produce ints is if I've marked "Tx complete" (in debug, I see the register and bits change). But I think this is a bit silly: this kind of interrupt is useful (very) if you have to do a RS485 control via soft and in combination of previous. If you are using hardware control or no use RS485, it's more logic use combination of other two ("empty" or "not full").
Can someone explain this behavior?