Nexus Development Interface (NDI)
PXN20 Microcontroller Reference Manual, Rev. 1
36-4 Freescale Semiconductor
• 22-bit full duplex pin interface for medium and high visibility throughput
— Only one mode is supported: full port mode (FPM). FPM comprises 12 MDO pins.
— Auxiliary output port
– One MCKO (message clock out) pin
– 12 MDO (message data out) pins
–Two MSEO (message start/end out) pins
– One EVTO (event out) pin
— Auxiliary input port uses one EVTI (event in) pin
— Five-pin JTAG port (JCOMP, TDI, TDO, TMS, and TCK)
• 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
— Generates asynchronous reset signal for Nexus blocks based on JCOMP input and power-on
reset status
• Host processor (e200z6) development support features (Nexus3+)
— IEEE-ISTO 5001-2003 standard class 3 compliant.
— 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.
— Data trace via data write messaging (DWM) and data read messaging (DRM). This allows the
development tool to trace reads and/or writes 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.
— Run-time access to the on-chip memory map via the JTAG port. This allows for enhanced
download/upload capabilities.
— Watchpoint messaging (WPM) via the auxiliary port.
— Watchpoint trigger enable of program and/or data trace messaging.
— Registers for Program Trace, Data Trace, Ownership Trace and Watchpoint Trigger.
— All features controllable and configurable via JTAG port.
• I/O co-processor (e200z0) development support features (Nexus2+)
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