Analog Interfacing to Embedded Microprocessor Systems, 2nd Edition

Interrupt Rates

The MAX151 can perform a conversion every 3:3 ms, or 300,000 conversions per

second. Even a 33 MHz processor operating at one instruction per clock cycle can

execute only 110 instructions in that time. The interrupt overhead of saving and

restoring registers can be a significant portion of those instructions.

In some applications, the processor does not need to process every conversion.

An example would be a design in which the processor takes four samples,

averages them, and then does something with the average. In cases like this,

using a processor with DMA capability can reduce the interrupt overhead. The

DMA controller is programmed ...