Programmed reference oscillator generates nonstandard clock frequencies

摘要

Although manufacturers offer crystal and ceramic resonators and packaged oscillators for many frequencies, nonstandard frequencies may not be readily available. When a unique integrator application required a 2021-Hz fixed-frequency clock, the circuit in Figure 1 solved the problem and required only a few extra and inexpensive components. The heart of the oscillator comprises a small assembly-language process that exploits equalized, fixed-lengtlybranch loops with only 12 instructions.