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IXP400 Software
Programmer’s Guide IXP400 Software Version 2.0 April 2005
Document Number: 252539, Revision: 007 293
Access-Layer Components:
UART-Access (IxUARTAcc) API 21
This chapter describes the Intel
®
IXP400 Software v2.0’s “UART-Access API” access-layer
component.
21.1 What’s New
There are no changes or enhancements to this component in software release 2.0.
21.2 Overview
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.
21.3 Interface Description
The API covers the following functions:
• Device initialization
• UART char output
• UART char input