Intel® Serial I/O Universal Asynchronous Receiver/Transmitter (UART) Controllers

The Processor implements three independent UART interfaces, UART0, UART1 and UART2. Each UART interface is a 4-wire interface supporting up to 6.25 Mbit/s.

The interfaces can be used in the low-speed, full-speed, and high-speed modes. The UART communicates with serial data ports that conform to the RS-232 interface protocol.

UART2 only implements the UART Host controller and does not incorporate a DMA controller which is implemented for UART0 and UART1. Therefore, UART2 is restricted to operate in PIO mode only.

The UART interfaces support the following features:

• Up to 6.25 Mbit/s Auto Flow Control mode as specified in the 16750 standard
• Transmitter Holding Register Empty (THRE) interrupt mode
• 64-byte TX and 64-byte RX host controller FIFOs
• DMA support with 64-byte DMA FIFO per channel (up to 32-byte burst)
• Functionality based on the 16550 industry standards
• Programmable character properties, such as number of data bits per character (5-8), optional parity bit (with odd or even select) and number of stop bits (1, 1.5, or 2)
• Line break generation and detection
• DMA signaling with two programmable modes
• Prioritized interrupt identification
• Programmable FIFO enable/disable
• Programmable serial data baud rate
• Modem and status lines are independently controlled
• Programmable BAUD RATE supported (baud rate = (serial clock frequency)/(16xdivisor))