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Nexus Port Controller (NPC)
JCOMP
TCK
TMS
TDI
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
1674
Debug
Reset
Mode
Control
Control
Message
Port
Transmitter
Arbiter
Register
JTAG
Control
Interface
Figure 37-1. Nexus Port Controller block diagram
MPC5644A Microcontroller Reference Manual, Rev. 6
PSTAT
EVTO
MDO Mux
Control
MDO/MSEO
Generation
Miscellaneous
Logic
TDO
Generation
MDO
MSEO_B
TDO
Freescale Semiconductor
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