
Hawk PCI Host Bridge & Multi-Processor Interrupt Controller
MVME5100 Single Board Computer Programmer’s Reference (6806800H17B
)
118
2.4.14.4 Interrupt Request Register (IRR)
There is a Interrupt Request Register (IRR) for each processor. The IRR always passes the output
of the IS except during Interrupt Acknowledge cycles. This guarantees that the vector which is
read from the Interrupt Acknowledge Register does not change due to the arrival of a higher
priority interrupt. The IRR also serves as a pipeline register for the two tick propagation time
through the IS.
2.4.14.5 In-Service Register (ISR)
There is a In-Service Register (ISR) for each processor. The contents of the ISR are the priority
and source of all interrupts, which are in-service. The ISR receives a bit-set command during
Interrupt Acknowledge cycles and a bit-clear command during End Of Interrupt cycles.
The ISR is implemented as a 40 bit register with individual bit set and clear functions. Fifteen
bits are used to store the priority level of each interrupt which is in-service. Twenty-five bits are
used to store the source identification of each interrupt which is in service. Therefore, there is
one bit for each possible interrupt priority and one bit for each possible interrupt source.
2.4.14.6 Interrupt Router
The Interrupt Router monitors the outputs from the ISR’s, Current Task Priority Registers,
Destination Registers, and the IRR’s to determine when to assert a processor’s INT pin.
When considering the following rule sets, it is important to remember that there are two types
of inputs to the Interrupt Selectors. If the interrupt is a distributed class interrupt, there is a
single bit in the IPR associated with this interrupt and it is delivered to both Interrupt Selectors.
This IPR bit is qualified by the destination register contents for that interrupt before the
Interrupt Selector compares its priority to the priority of all other requesting interrupts for that
processor. If the interrupt is programmed to be edge sensitive, the IPR bit is cleared when the
vector for that interrupt is returned when the Interrupt Acknowledge register is examined. On
the other hand, if the interrupt is a direct/multicast class interrupt, there are two bits in the IPR
associated with this interrupt. One bit for each processor.
Then one of these bits is delivered to each Interrupt Selector. Since this interrupt source can be
multicast, each of these IPR bits must be cleared separately when the vector is returned for that
interrupt to a particular processor.
Содержание MVME5100
Страница 1: ...MVME5100 Single Board Computer Programmer s Reference P N 6806800H17B July 2014...
Страница 8: ...MVME5100 Single Board Computer Programmer s Reference 6806800H17B Contents 8 Contents Contents...
Страница 16: ...MVME5100 Single Board Computer Programmer s Reference 6806800H17B 16 List of Figures...
Страница 62: ...Product Data and Memory Maps MVME5100 Single Board Computer Programmer s Reference 6806800H17B 62...
Страница 292: ...Hawk Programming Details MVME5100 Single Board Computer Programmer s Reference 6806800H17B 292...
Страница 308: ...MVME5100 VPD Reference Information MVME5100 Single Board Computer Programmer s Reference 6806800H17B 308...
Страница 312: ...VMEbus Mapping Example MVME5100 Single Board Computer Programmer s Reference 6806800H17B 312...
Страница 316: ...Related Documentation MVME5100 Single Board Computer Programmer s Reference 6806800H17B 316...
Страница 317: ......