Intel IXP400 manual Access-Layer Components UART-Access IxUARTAcc API, Interface Description

Intel® IXP400 Software

Access-Layer Components:	21
UART-Access (IxUARTAcc) API

This chapter describes the Intel® IXP400 Software v2.0’s “UART-Access API” access-layer component.

21.1What’s New

There are no changes or enhancements to this component in software release 2.0.

21.2Overview

The UARTs of the Intel® IXP4XX Product Line of Network Processors and IXC1100 Control Plane Processor have been modeled on the industry standard 16550 UART. There are, however, some differences between them which prevents the unmodified use of 16550-based UART drivers. They support baud rates between 9,600 bps and 912.6 Kbps.

The higher data rates allow the possibility of using the UART as a connection to a data path module, such as Bluetooth*. While the UART is instantiated twice on the IXP4XX product line and IXC1100 control plane processors, the same low-level routines will be used by both. The default configuration for the processor is:

•UART0 — Debug Port (console)

•UART1 — Fast UART (e.g., Bluetooth)

Any combination of debug or high-speed UART, however, could be used.

A generic reference implementation is provided that can be used as an example for other implementations/operating systems. These routines are meant to be stand-alone, such that they do not require an operating system to execute. If a new operating system is later added to those supported, these routines can be easily modified to link in to that platform, without the need for extensive rework.

The UART driver provides generic support for polled and loop back mode only.

21.3Interface Description

The API covers the following functions:

•Device initialization

•UART char output

•UART char input

Programmer’s Guide	IXP400 Software Version 2.0	April 2005
	Document Number: 252539, Revision: 007	293