![Texas Instruments AM1808 Technical Reference Manual Download Page 1502](http://html.mh-extra.com/html/texas-instruments/am1808/am1808_technical-reference-manual_10945581502.webp)
Introduction
1502
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Asynchronous Receiver/Transmitter (UART)
31.1 Introduction
31.1.1 Purpose of the Peripheral
The UART peripheral is based on the industry standard TL16C550 asynchronous communications
element, which in turn is a functional upgrade of the TL16C450. Functionally similar to the TL16C450 on
power up (single character or TL16C450 mode), the UART can be placed in an alternate FIFO
(TL16C550) mode. This relieves the CPU of excessive software overhead by buffering received and
transmitted characters. The receiver and transmitter FIFOs store up to 16 bytes including three additional
bits of error status per byte for the receiver FIFO.
The UART performs serial-to-parallel conversions on data received from a peripheral device and parallel-
to-serial conversion on data received from the CPU. The CPU can read the UART status at any time. The
UART includes control capability and a processor interrupt system that can be tailored to minimize
software management of the communications link.
The UART includes a programmable baud generator capable of dividing the UART input clock by divisors
from 1 to 65535 and producing a 16× reference clock or a 13× reference clock for the internal transmitter
and receiver logic. For detailed timing and electrical specifications for the UART, see your device-specific
data manual.
31.1.2 Features
Check your device-specific data manual to see the list of features that are supported and that are not
supported by the UART.
31.1.3 Functional Block Diagram
A functional block diagram of the UART is shown in
.
31.1.4 Industry Standard(s) Compliance Statement
The UART peripheral is based on the industry standard TL16C550 asynchronous communications
element, which is a functional upgrade of the TL16C450. The information in this chapter assumes you are
familiar with these standards.