Datasheet

163
8023F–AVR–07/09
ATmega325P/3250P
18. USART0
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
18.2 Overview
The Universal Synchronous and Asynchronous serial Receiver and Transmitter (USART) is a
highly flexible serial communication device.
A simplified block diagram of the USART Transmitter is shown in Figure 18-1 on page 164. CPU
accessible I/O Registers and I/O pins are shown in bold.
The Power Reduction USART bit, PRUSART0, in ”PRR – Power Reduction Register” on page
44 must be written to zero to enable USART0 module.