1.8-V To 5-V Dual UART With 16-Byte FIFOs

The TL16C2552 is a dual universal asynchronous receiver andtransmitter (UART). It incorporates the functionality of two TL16C550D UARTs each UART having its own Register set and FIFOs The two UARTs share only the data bus Interface and Clock source, otherwise they operate independently. Another name for the UART function is Asynch 1340 ronous Communications Element (ACE), and these terms will be used interchangeably. The bulk of this document describes the behavior of each ACE, with the understanding that two such devices are incorporated into the TL16C2552.
Each ACE is a speed and voltage range upgrade of the TL16C550C which in turn is a functional upgrade of the TL16C450. Functionally equivalent to the TL16C450 on power up or reset (single character or TL16C450 mode), each ACE CAN be placed in an alternate FIFO mode. This relieves the CPU of excessive software overhead by buffering received and to be transmitted characters. Each receiver and transmitter store up to 16 bytes in their respective FIFOs with the receive FIFO including three additional bits per byte for error status. In the FIFO mode, a selectable autoflow control feature CAN significantly reduce software overload and increase system efficiency by automatically controlling serial data flow using handshakes between the RTS
By Texas Instruments