5 Conclusion
The AVR® core utilization results are summarized in the table below. A column for a CPU clock of 20 MHz is also provided since many AVR® devices have this clock speed as an upper limit.
| Demodulator Type | ADC Sample Rate | FIR Filter Taps | Downsampling Factor | AVR® Core Utilization (16 MHz Clock) | AVR® Core Utilization (20 MHz Clock) |
|---|---|---|---|---|---|
| AFSK | 6250 Hz | - | 1 | 29.3% | 23.4% |
| AFSK with additional filtering | 12500 Hz | 15 | 2 | 61.9% | 49.5% |
| Near-ultrasonic FSK | 50000 Hz | 9 | 8 | 66.6% | 53.3% |
These results confirm that the 8-bit AVR® core is capable of high levels of performance, even when the application requires some digital signal processing and is written in a high-level language. Next time you're evaluating microcontrollers for a project that involves sampling an analog signal with an ADC and performing some processing of that signal, consider prototyping it on an 8-bit AVR® microcontroller. Its performance, coupled with its low-power consumption and low cost, may surprise you.