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1745D–ATARM–04-Nov-05
AT91M55800A
18. USART: Universal Synchronous/ Asynchronous Receiver/Transmitter
The AT91M55800AA provides three identical, full-duplex, universal synchronous/asynchro-
nous receiver/transmitters which are connected to the Peripheral Data Controller.
The main features are:
• Programmable Baud Rate Generator
• Parity, Framing and Overrun Error Detection
• Line Break Generation and Detection
• Automatic Echo, Local Loopback and Remote Loopback channel modes
• Multi-drop Mode: Address Detection and Generation
• Interrupt Generation
• Two Dedicated Peripheral Data Controller channels
• 5-, 6-, 7-, 8- and 9-bit character length
Figure 18-1. USART Block Diagram
Peripheral Data Controller
Receiver
Channel
Transmitter
Channel
Control Logic
Interrupt Control
Baud Rate Generator
Receiver
Transmitter
AMBA
ASB
APB
USxIRQ
MCK
MCK/8
RXD
TXD
SCK
USART Channel
Baud Rate Clock
PIO:
Parallel
I/O
Controller