Abstract: A programmable crystal oscillator that generates a wide range of possible frequencies with high stability is disclosed. The programmable crystal clock oscillator includes an industry standard oscillator package, a programmable storage, a crystal and a phase lock loop (PLL) circuit coupled to the crystal and the programmable storage. The industry standard package does not contain any dedicated programming connections. A programmable storage, contained within the package, stores parameters representing a desired output frequency for the crystal oscillator. The crystal is enclosed within the package and provides a source frequency. The PLL circuit, also enclosed in the package, receives the source frequency, and produces the desired output frequency, within the wide range of possible frequencies, based on the parameters.