Programmable oscillator circuit and method

A timing circuit comprising:

• a programmable load circuit adapted to be coupled to a crystal to receive a source frequency;
• an oscillator circuit adapted to be coupled to receive said source frequency;
• a frequency multiplier circuit coupled to said oscillator circuit to receive said source frequency;
• and
• a programming circuit configured to supply stored first programming data to said programmable load circuit to adjust said source frequency and stored second programming data to said frequency multiplier circuit, such that said frequency multiplier circuit supplies an output frequency which is substantially equal to a product of said adjusted source frequency and a multiplication factor designated by said second programming data.

A programmable timing circuit comprising:

• an oscillator circuit adapted to be coupled to excite a crystal into generating a source frequency;
• a capacitive load circuit adapted to be coupled to said crystal and configured to be programmed by stored programming data to a desired load capacitance, such as to selectively adjust said source frequency;
• and
• a phase locked loop circuit coupled to said oscillator circuit, said phase locked loop circuit for generating an output frequency as a product of said adjusted source frequency and a multiplication factor.

A programmable oscillator circuit, comprising:

• an oscillator circuit;
• input lines coupled to said oscillator circuit;
• a programmable capacitive load, coupled to said input lines, to provide a load the input lines;
• a phase locked loop circuit coupled to the oscillator circuit for generating a loop frequency in response to an output of the oscillator circuit and the programmable capacitive load, said phase locked loop circuit operating on said loop frequency by using a frequency parameter to generate a phase locked loop output frequency;
• and
• a programming circuit coupled to said programmable capacitive load circuit and to said phase locked loop circuit, said programming circuit storing said loading and frequency parameters for respectively programming said capacitive load circuit and said phase locked loop circuit.

An electrical-circuit unit for providing an output frequency, comprising:

• a programmable load circuit;
• an oscillator circuit connected to the programmable load circuit;
• a phase lock loop connected to said oscillator circuit for generating a frequency in response to the oscillator circuit and the programmable load circuit;
• an electrically-programmable memory for storing first programming data for adjusting said programmable load circuit and for storing second programming data for adjusting said phase lock loop;
• and
• a memory controller for receiving an external input from outside the electrical-circuit unit used in controlling the storage of the first and second programming data.

An integrated circuit comprising:

• a programmable capacitive load circuit including a set of selectable impedances and a set of semiconductor switches, each one of the set of switches coupled respectively to one of the selectable impedances;
• an oscillator circuit connected to the programmable load circuit;
• a phase lock loop connected to said oscillator circuit for generating a frequency in response to the oscillator circuit and the programmable capacitive load circuit;
• a memory for storing first programming data for selecting impedances by turning particular switches of said programmable capacitive load circuit on or off, and for storing a feed back value of the phase lock loop (P) and a reference value for the phase lock loop (Q);
• and
• control logic configured to permit an external input from outside the integrated circuit to cause the memory to store said first programming data, said feedback value (P), and said reference value (Q).

A crystal oscillator tuning circuit comprising:

• an oscillator circuit adapted to be coupled to a crystal, the oscillator circuit capable of producing a reference frequency;
• a programmable capacitor tuning circuit coupled to the oscillator circuit;
• a frequency multiplier circuit coupled to the oscillator circuit;
• and
• means for storing data, said means being operatively connected to the programmable capacitor tuning circuit and the frequency multiplier circuit,
• wherein the stored data includes data used to selectively adjust the capacitance of the capacitor tuning circuit and data used to selectively adjust the multiplication factor of the frequency multiplier circuit, and
• wherein the programmable capacitor tuning circuit and the frequency multiplier circuit are adapted to modify the reference frequency to produce an output clock frequency.

A programmable phase lock loop and oscillator tuning circuit comprising:

• an oscillator circuit;
• a programmable capacitor load circuit coupled to the oscillator circuit;
• a phase lock loop circuit coupled to the oscillator circuit;
• and
• a programmable memory operatively connected to the programmable capacitor load circuit and the phase lock loop circuit,
• wherein the memory stores a capacitor load value used to selectively adjust the capacitance of the capacitor load circuit, a feedback value for the phase lock loop (P), and a reference value for the phase lock loop (Q), and
• wherein the programmable capacitor load circuit and the phase lock loop circuit are adapted to modify a reference frequency for producing an output frequency.

An electrical-circuit unit for providing an output frequency, comprising:

• programmable load circuit means for providing a programmable load;
• an oscillator circuit means connected to the programmable load circuit means;
• a frequency generating means, including a phase lock loop connected to said oscillator circuit means, for generating a frequency in response to an output of the oscillator circuit means and the programmable load circuit means;
• a memory means for storing first programming data for adjusting said programmable load circuit means and for storing second programming data for adjusting said frequency generating means;
• and
• a memory controller means for receiving an external input from outside the electrical-circuit unit to control the storage of the first and second programming data.