In message 12896654.post@talk.nabble.com you wrote:
Our program based on U-BOOT and we need transmit data at UART-TX with interrupts.
What makes you think you need interrupts? U-Boot is strictly single tasking, so it will not do anything else anyway while transmitting, and even a very slow CPU should be capable of streaming characters out or an UART then.
But, as we understand, U-BOOT do not have "API" for correct realization Interrupts, we fount in cpu/bf532/serial.c each initialization with as-be usage Interrupts, but not used it, because only doing looping ISR register on FLAG IRQ_UART_TX_BIT.
Indeed polling is all you need.
It is not correct usage Interrupts. We need full usage interrupts.
What makes you think so? Interrupts will not give you any advantages.
Best regards,
Wolfgang Denk