NXP Semiconductors MPC5644A, Reference Manual, Page: 684 / 1735

Configurable Enhanced Modular IO Subsystem (eMIOS200)
MPC5644A Microcontroller Reference Manual, Rev. 6
684 Freescale Semiconductor
2. Write the desired value for prescaling rate at UCPRE[0:1] bits in EMIOS_CCR[n];
3. Enable channel prescaler by writing ‘1’ at UCPREN bit in EMIOS_CCR[n];
4. Enable global prescaler by writing ‘1’ at bit EMIOS_MCR[GPREN].
The prescaler is not disabled during either freeze state or negated GTBE input.
22.5.1.4 Effect of freeze on the unified channel
When in debug mode, bit EMIOS_MCR[FRZ] and the FREN bit in the EMIOS_CCR[n] are both set, the
internal counter and channel capture and compare functions are halted. The channel is frozen in its current
state.
During freeze, all registers are accessible. When the channel is operating in an output mode, the force
match functions remain available, allowing the software to force the output to the desired level.
Note that for input modes, any input events that may occur while the channel is frozen are ignored.
When exiting debug mode or freeze enable bit is cleared (bit EMIOS_MCR[FRZ] or FREN in the
EMIOS_CCR[n]), the channel actions resume but may be inconsistent until the channel enters GPIO mode
again.
22.5.2 IP bus interface unit (BIU)
The BIU provides the interface between the Internal Interface Bus (IIB) and the Peripheral Bus, allowing
communication among all submodules and this IP interface.
The BIU allows 8, 16 and 32 bits access. They are performed over a 32-bit data bus in a single cycle clock.
22.5.2.1 Effect of freeze on the BIU
When bit EMIOS_MCR[FRZ] is set and the module is in debug mode, the operation of BIU is not affected.
22.5.3 STAC client submodule
The shared time and angle count (STAC) bus provides access to one external time base, imported from the
STAC bus to the eMIOS unified channels. The eTPU module’s time bases and angle count can be exported
and/or imported through the STAC client submodule interface. Time bases and/or angle information of the
eTPU engine can be exported to the eMIOS module, which is only a STAC client. There are restrictions
on engine export/import targets: an engine cannot export from or import to itself, nor can it import time
base and/or angle count if in angle mode.
The device’s STAC server identification assignment is shown in Table 22-11 . The time slot assignment is
fixed, so only time bases running at system clock divided by four or slower can be integrally exported. The
STAC client submodule runs with the system clock, and its time slot timing is synchronized with the eTPU
timing on reset. The time slot sequence is 0-1-2-3.