![](http://datasheet.mmic.net.cn/90000/MC80C32E-12-883-D_datasheet_2371307/MC80C32E-12-883-D_175.png)
175
8272E–AVR–04/2013
ATmega164A/PA/324A/PA/644A/PA/1284/P
19. USART
19.1
Features
Full duplex operation (independent serial receive and transmit registers)
Asynchronous or synchronous operation
Master or Slave clocked synchronous operation
High resolution baud rate generator
Supports Serial Frames with 5, 6, 7, 8, or 9 data bits and 1 or 2 stop bits
Odd or even parity generation and parity check supported by hardware
Data OverRun detection
Framing Error detection
Noise filtering includes False Start bit detection and Digital Low Pass Filter
Three separate interrupts on TX complete, TX Data Register Empty and RX Complete
Multi-processor Communication mode
Double Speed Asynchronous Communication mode
19.2
USART1 and USART0
The Atmel ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P has two USART’s,
USART0 and USART1.
The functionality for all USART’s is described below, most register and bit references in this sec-
tion are written in general form. A lower case “n” replaces the USART number.
19.3
Overview
The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a
highly flexible serial communication device.
accessible I/O Registers and I/O pins are shown in bold.
page 48 must be disabled by writing a logical zero to it.
page 49 must be disabled by writing a logical zero to it.