NXP Semiconductors MPC5644A, Reference Manual, Page: 1674 / 1735

Nexus Port Controller (NPC)
MPC5644A Microcontroller Reference Manual, Rev. 6
1674 Freescale Semiconductor
Figure 37-1. Nexus Port Controller block diagram
37.2.1 Overview
On a system-on-chip device, there are often multiple blocks that require development support. Each of
these blocks implements a development interface based on the IEEE-ISTO 5001-2001 standard. The
blocks share input and output ports that interface with the development tool. The NPC controls the usage
of the input and output port in a manner that allows all the individual development interface blocks to share
the port, and appear to the development tool to be a single block.
37.2.2 Features
The NPC block performs the following functions:
• Controls arbitration for ownership of the Nexus Auxiliary Output Port
• Nexus Device Identification Register and Messaging
• Generates MCKO enable and frequency division control signals
• Controls sharing of EVTO
• Generates an MCKO clock gating control signal to enable gating of MCKO when the auxiliary
output port is idle
• Control of the device-wide debug mode
Port
Arbiter
Message
Transmitter
MDO/MSEO
Generation
JTAG
TDI
TDO
TCK
TMS
Debug
Mode
Control
Register
TDO
Generation
Reset
Control
JCOMP
EVTO
Control
Control
Interface
PSTAT
MDO Mux
MDO
MSEO_B
Miscellaneous
Logic