Crystal oscillator having input/output pins selectively used for analog or digital signals
US5724009A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1996 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | Oct 29, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L1/026
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital temperature compensated crystal oscillator (10) with pin multiplex control which includes: four analog I/O pins, a signal multiplex method which allows switchable digital communication via at least two of the analog I/O pins (20,28), and an external mode selector (12) which operates through the power leads. Changes in the power voltage level selects the TCXO (10) to operate in a normal or communication operating mode. In the normal operating mode the TCXO operates in a normal analog manner. In the communication mode, the analog functions of the I/O pins (20,28) are switched out and digital functions are allowed on the same I/O pins (20,28). The use of the same I/O pins (20,28) for switchable analog and digital signals saves size and cost, and prevents the inadvertent access to the digital functions of the TCXO (10) by customers in the field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.