PXS20 Datasheet, PDF (22/119 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Introduction
1.5.41 Nexus Port Controller (NPC)
The NPC module provides real-time development support capabilities for this device in compliance with the IEEE-ISTO
5001-2008 standard. This development support is supplied for MCUs without requiring external address and data pins for
internal visibility.
The NPC block interfaces to the host processor and internal buses to provide development support as per the IEEE-ISTO
5001-2008 Class 3+, including selected features from Class 4 standard.
The development support provided includes program trace, data trace, watchpoint trace, ownership trace, run-time access to the
MCUs internal memory map and access to the Power Architecture^® internal registers during halt. The Nexus interface also
supports a JTAG only mode using only the JTAG pins. The following features are implemented:
• Full and reduced port modes
• MCKO (message clock out) pin
• 4 or 12 MDO (message data out) pins¹
• 2 MSEO (message start/end out) pins
• EVTO (event out) pin
— Auxiliary input port
• EVTI (event in) pin
• 5-pin JTAG port (JCOMP, TDI, TDO, TMS, and TCK)
— Supports JTAG mode
• Host processor (e200) development support features
— Data trace via data write messaging (DWM) and data read messaging (DRM). This allows the development tool
to trace reads or writes, or both, to selected internal memory resources.
— Ownership trace via ownership trace messaging (OTM). OTM facilitates ownership trace by providing visibility
of which process ID or operating system task is activated. An ownership trace message is transmitted when a
new process/task is activated, allowing development tools to trace ownership flow.
— Program trace via branch trace messaging (BTM). Branch trace messaging displays program flow discontinuities
(direct branches, indirect branches, exceptions, etc.), allowing the development tool to interpolate what
transpires between the discontinuities. Thus, static code may be traced.
— Watchpoint messaging (WPM) via the auxiliary port
— Watchpoint trigger enable of program and/or data trace messaging
— Data tracing of instruction fetches via private opcodes
1. 4 MDO pins on 144 LQFP package, 12 MDO pins on 257 MAPBGA package.
PXS20 Microcontroller Data Sheet, Rev. 1
22
Preliminary—Subject to Change Without Notice
Freescale Semiconductor