MOTOROLA
Chapter 4. System Interface Unit (SIU)
4-9
Part II. ConÞguration and Reset
If the software watchdog timer is programmed to generate an interrupt, it always generates
a machine check interrupt to the core. The external IRQ0 can generate MCP as well. Note
that the core takes the machine check interrupt when MCP is asserted; it takes an external
interrupt for any other interrupt asserted by the interrupt controller.
The interrupt controller allows masking of each interrupt source. Multiple events within a
CPM sub-block event are also maskable.
All interrupt sources are prioritized and bits are set in the interrupt pending register
(SIPNR). On the MPC8260, the prioritization of the interrupt sources is ßexible in the
following two aspects:
¥
The relative priority of the FCCs, SCCs, and MCCs can be modiÞed
¥
One interrupt source can be assigned the highest priority
When an unmasked interrupt source is pending in the SIPNR, the interrupt controller sends
an interrupt request to the core. When an exception is taken, the interrupt mask bit in the
machine state register (MSR[EE]) is cleared to disable further interrupt requests until
software can handle them.
The SIU interrupt vector register (SIVEC) is updated with a 6-bit vector corresponding to
the sub-block with the highest current priority.
4.2.2 Interrupt Source Priorities
The interrupt controller has 37 interrupt sources that assert one interrupt request to the core.
Table 4-2 shows prioritization of all interrupt sources. As described in following sections,
ßexibility exists in the relative ordering of the interrupts, but, in general, relative priorities
are as shown. A single interrupt priority number is associated with each table entry.
Note that the group and spread options, shown with YCC entries in Table 4-2, are described
in Section 4.2.2.1, ÒSCC, FCC, and MCC Relative Priority.Ó
Table 4-2. Interrupt Source Priority Levels
Priority Level
Interrupt Source Description
Multiple Events
1
Highest
Ñ
2
XSIU1
No (TMCNT,PIT = Yes)
3
XSIU2 (GSIU = 0)
No (TMCNT,PIT = Yes)
4
XSIU3 (GSIU = 0)
No (TMCNT,PIT = Yes)
Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
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Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
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Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
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