Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Плата / Вычислитель / Atmel-2549-8-bit-AVR-Microcontroller-ATmega640-1280-1281-2560-2561_datasheet.pdf
Скачиваний:
24
Добавлен:
10.02.2015
Размер:
8.82 Mб
Скачать

22. USART

22.1Features

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

22.2Overview

The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a highly flexible serial communication device.

The ATmega640/1280/2560 has four USART’s, USART0, USART1, USART2, and USART3. The functionality for all four USART’s is described below. USART0, USART1, USART2, and USART3 have different I/O registers as shown in “Register Summary” on page 399.

A simplified block diagram of the USART Transmitter is shown in Figure 22-1 on page 201. CPU accessible I/O Registers and I/O pins are shown in bold.

The Power Reducion USART0 bit, PRUSART0, in “PRR0 – Power Reduction Register 0” on page 55 must be disabled by writing a logical zero to it.

The Power Reducion USART1 bit, PRUSART1, in “PRR1 – Power Reduction Register 1” on page 56 must be disabled by writing a logical zero to it.

The Power Reducion USART2 bit, PRUSART2, in “PRR1 – Power Reduction Register 1” on page 56 must be disabled by writing a logical zero to it.

The Power Reducion USART3 bit, PRUSART3, in “PRR1 – Power Reduction Register 1” on page 56 must be disabled by writing a logical zero to it.

ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]

200

2549Q–AVR–02/2014