MPC555
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MPC556
SYSTEM CONFIGURATION AND PROTECTION
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
6-10
ority levels. Each one of the SIU internal interrupt sources, as well as the interrupt re-
quests generated by the IMB3 modules, can be assigned by the software to any one
of those eight interrupt priority levels.
The same interrupt request signal that is generated within the RCPU is optionally driv-
en on the IRQ_OUT pin. This pin may be used in peripheral mode, in which the internal
processor is shut off and the internal modules are accessed externally.
The IMB3 interrupts are controlled by the UIMB. The IMB3 provides 32 interrupt levels.
Any interrupt source can be configured to any IMB3 interrupt level. The 32-bit UIPEND
register in the UIMB holds the pending IMB3 interrupt requests. IMB3 interrupt request
levels zero to six are mapped to USIU interrupt levels zero to six, respectively. IMB3
interrupt request levels seven to 31 are mapped to USIU request level seven. The user
must read the UIPEND register to determine the actual source of the interrupt. Refer
to
for more information.
NOTE
If the same interrupt level is assigned to more than one source, soft-
ware must read the appropriate status bits in the appropriate UIMB3
registers to determine which interrupt was asserted.
illustrates the operation of the interrupt controller.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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