Datasheet

185
4317K–AVR–03/2013
AT90PWM2/3/2B/3B
18. USART
The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a
highly flexible serial communication device. The main features are:
18.1 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
• USART Extended mode (EUSART) with:
– Independent bit number configuration for transmit and receive
– Supports Serial Frames with 5, 6, 7, 8, 9 or 13, 14, 15, 16, 17 Data Bits and 1 or 2 Stop Bits
– Biphase Manchester encode/decoder (for DALI Communications)
– Manchester framing error detection
– Bit ordering configuration (MSB or LSB first)
– Sleep mode exit under reception of EUSART frame
18.2 Overview
A simplified block diagram of the USART Transmitter is shown in Figure 18-1. CPU accessible
I/O Registers and I/O pins are shown in bold.