Uart Overview - Texas Instruments UCD3138 Technical Reference Manual

UCD3138 has two UART modules capable of independently communicating toward two separate peers.
Having more than one UART module is also especially useful for power supplies than need to
communicate with an isolated section (eg. with the digital PFC controller, or a Power Metering ASIC in
offline AC/DC power supplies) through opto-isolators.
While one UART module is serving communication needs over an isolation barrier, the other UART may
be used for communicating with a HOST or serve debugging needs.
This section provides an overview of these UART modules. Table below contains a brief description of the
UART, lists its significant pins and described interrupts.
Description
Pins
Interrupts
Features
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Topic
12.1 UART Frame Format
12.2 Asynchronous Timing Mode
12.3 UART Interrupts
12.4 Transmit Interrupt
12.5 Receive Interrupt
12.6 Error Interrupts
12.7 UART Registers Reference
SNIU028A – February 2016 – Revised April 2016
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The UART module is a universal asynchronous receiver-transmitter that implements the standard
non-return to zero format. The UART module can be used to communicate, for example, through
an RS-232 port or over a K-line.
SCI_Rx UART receive pin
SCI_Tx UART transmit pin
The UART has three interrupts: transmit, receive, and error. Each interrupt can be individually
enabled.
• Standard universal asynchronous receiver-transmitter (UART) communication
• Supports full- or half-duplex operation
• Standard nonreturn to zero (NRZ) format
• Double-buffered receive and transmit functions
• Configurable frame format of 3 to 13 bits per character based on the following:
• Data word length programmable from one to eight bits
• Parity programmable for zero or one parity bit, odd or even parity
• Stop programmable for one or two stop bits
• The 24-bit programmable baud rate supports 224 different baud rates provide high accuracy
baud rate selection
• Four error flags and six status flags provide detailed information regarding UART events
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Copyright © 2016, Texas Instruments Incorporated
SNIU028A – February 2016 – Revised April 2016

UART Overview

UART Overview
Chapter 12
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