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P4080 Development System User’s Guide, Rev. 0
32
Freescale Semiconductor
Architecture
VELA
VELA is a simple machine to monitor requested changes in board configuration
and when detected, perform a power-on-reset/re-configuration of the target
system.
OCM
Offline configuration manager—a machine that initializes the ngPIXIS registers,
including those used for P4080 initialization, from external I
2
C EEPROMs. The
OCM can talk to the user or another computer using the serial port while the
system is powered down.
GMSA
General microprocessor/stack architecture—a stack-based microprocessor that
loads executes before and during power-down/-up events. It can query I
2
C devices
and collect data during normal system operation, as well as allow setting
configuration switches without opening the chassis.
5.2.1
COP
COP handles merging COP header resets with on-board resets in a transparent manner. It is critical that the
COP HRST* input resets the entire system except for the COP JTAG controller (that is, TRST* must not
be asserted). With COP not attached, it is critical that reset does indeed assert TRST*. The COP core
manages these modal operations.
5.2.2
RESETSEQ
RESETSEQ collects various reset/power-good signals and starts the global reset sequencer.
Note that ASLEEP indicates that the processors(s) have exited the reset state. It does not cause a reset,
because the processor can sleep for any number of reasons after hard reset is completed.
Note also that during power-down, all I/O and output drivers must be tristated. After power up, drivers
may be driven. Normal operation and/or use of the VELA engine may cause some I/Os to be tristated.
5.2.3
REGRESETS
REGRESETS copies reset signals from the sequencer, but also allows register-based software to
individually asserted reset to the local bus, memory, and/or compact Flash interfaces.
5.2.4
REGFILE
REGFILE is a dual-ported register file containing several types of registers.
Note that REGFILE must be able to accept (or arbitrate for) concurrent writes to the same register, though
this is not a statistically likely occurrence.
5.2.5
LOCALBUS
LOCALBUS is the interface between processor and REGFILE. Because access to the internal registers
may be blocked, asynchronous (not ready) signalling is used.