Analysis of information sources in references of the Wikipedia article "16550 UART" in English language version.
The primary difference between these two parts is in the operation of the FIFOs. The NS16550 will sometimes transfer extra characters when the CPU reads the RX FIFO. Due to the asynchronous nature of this failure there is no work-around and the NS16550 should NOT be used in the FIFO mode. The NS16550A has no problems operating in the FIFO mode and should be used on all new designs.
