The pitfall of UART

The UART controller of ADSP-BF533 is 16450 compatible. If you used to program PC since ‘80th or know well about IPs, you may realize that this doesn’t have FIFO buffer. No PC uses this these days. The buffered type 16550A was developed to prevent the data under run of receiving with old slow PC-DOS. But these days embedded processor has enough speed and RTOS has good interrupt response type. Then, for embedded application, FIFO doesn’t matter so match.
You must be careful about pitfall if you use UART of BF533. Not FIFO. That is UART_GCTL register which does not exist on original 16650. This register contains additional control bits like IrDA mode. And it does has UCEN ( UART Clock Enable ) bit which enables clocking to UART module. If you set this bit 0, you can stop the clock to UART and can decrease the current consumption. The problem is it’s default. UCEN is 0 after reset, then, you can not use UART until you explicitly set this bit to 1.
You should be sure to set this bit 1 before you access the UART registers.