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DESIGNING WITH THE MMC2107

by David Gonzales

Start ý System Overview ý On-Chip Memory Arrays ý Receiving and Servicing Real-Time Interrupts ý Asynchronous and Synchronous Communication ý Measuring, Timing, Creating ý Collecting Analog Information ý System Features ý Sources and PDF

RECEIVING AND SERVICING REAL-TIME INTERRUPTS

A key task in an embedded microcontroller is to rapidly service one or more interrupt inputs. Interrupts may come from a variety of sources and their intervals can vary in time from >1 s to <10 ýs. Therefore, it is important to evaluate the worst-case conditions of interrupt latency. It is also important to understand how many interrupts may be serviced, whether or not you are able to turn them off, and to prioritize the interrupts in hardware and software.

The MMC2107 uses a combination of M-CORE processor and interrupt controller features to handle interrupts. It can service as many as 40 interrupt sources using 32 unique programmable priority levels for each interrupt source. Each interrupt source is maskable, and each priority level can be programmed for normal or fast interrupt requests, where they always have priority over normal interrupts. The interrupt input ports may be uniquely programmed to be edge- or level-triggered.

Interrupt requests may be vectored or auto-vectored. Vectored interrupts are generated based on priority level. Separate vector numbers are available for normal and fast interrupts to facilitate rapid service handling. The software can self-schedule interrupts using status information on pending interrupts. The interrupt controller is not affected by any low-power modes. All logic between the input sources and the M-CORE processor interrupt signals are combinatorial. This permits the M-CORE processor to wake up during low-power stop mode when all system clocks are stopped.

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