Motorola MVME2300 Series manual Interrupt Delivery Modes

Models: MVME2300 Series

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Interrupt Delivery Modes

The direct and distributed interrupt delivery modes are supported. Note that the direct delivery mode has sub modes of multicast or non-multicast. The Interprocessor Interrupts (IPIs) and Timer interrupts operate in the direct delivery mode. The externally sourced or I/O interrupts operate in the distributed mode.

In direct delivery mode, the interrupt is directed to one or both processors. If it is directed to two processors (i.e. multicast), it will be delivered to two processors. The interrupt is delivered to the processor when the priority of the interrupt is greater than the priority contained in the task register for that processor, and when the priority of the interrupt is greater than any interrupt which is in-service for that processor. An interrupt is considered to be in service from the time its vector is returned during an interrupt acknowledge cycle until an EOI is received for that interrupt. The EOI cycle indicates the end of processing for the highest-priority in-service interrupt.

In distributed delivery mode, the interrupt is pointed to one or more processors but it will be delivered to only one processor. Therefore, for externally sourced or I/O interrupts, multicast delivery is not supported.The interrupt is delivered to a processor when the priority of the interrupt is greater than the priority contained in the task register for that processor, and when the priority of the interrupt is greater than any interrupt which is in-service for that processor, and when the priority of that interrupt is the highest of all interrupts pending for that processor, and when that interrupt is not in-service for the other processor. If both destination bits are set for each processor, the interrupt will be delivered to the processor that has a lower task register priority.

Note Because a deadlock condition can occur when the task register priorities for each processor are the same and both processors are targeted for interrupt delivery, the interrupt will be delivered to processor 0.

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Motorola MVME2300 Series manual Interrupt Delivery Modes