下载
© Freescale Semiconductor, Inc., 2004. All rights reserved.
Freescale Semiconductor
Application Note
AN2693
Rev. 0, 01/2005
Table of Contents
The MPC565 was the first publicly available
microcontroller to feature a Nexus Interface (IEEE-ISTO
5001™-1999
1
Nexus Class 3). It allows advanced debug
capabilities by providing high-speed access to the
microcontroller core. These advanced debug capabilities
include trace, without requiring extensive external
circuitry to monitor an external address bus. The Nexus
standard, as implemented on the MPC56x, is referred to
as the Real-time Embedded Application Development
Interface (READI). Revision D of the MPC565, revision
D of the MPC561, and revision C of the MPC563 have
an updated version of the READI module that includes
new features that are described in this application note.
These features are not available in earlier versions of
these devices.
These changes address issues found with the Nexus
standard and the READI implementation of the Nexus
standard. The changes include an additional Nexus
register accessible by the Nexus tool to enable new
options, additional error codes, updated manufacturer
1. Nexus 5001-1999 (Version 1.0) was the initial release of the
standard, however the Nexus 5001-2003 was released in 2003.
The MPC56x does include some features from the 2003 release.
1 Identification of the Updated READI Module.......2
2 READI Tool Registers..........................................3
3 Nexus Public and Vendor Defined Messages......7
4 Nexus Message Queue Size .............................17
5 READI Priorities ................................................18
6 Number of Clocks Between MDI Messages ......19
7 Hints for Debugging Using Nexus......................19
8 READI Module Design Changes .......................24
9 Revision History ................................................26
New Features of the MPC56x
READI Nexus Interface Module
by: Randy Dees & Bryan Weston
TECD Applications & Design
