Programmable Quartz Oscillator

Description

This homebrewing project is my first attempt with a programmable XO. The PXO Si570 is a very interesting part for homebrewers as second LO, as VCO for your SDR or HDR experiments or as simple signal generator.

For evaluation purposes I designed February/March 2008 a small Si570 evaluation board with the Si570 chip, a GTL2002 bidirectional voltage translator as I2C interface and a DS90LV018A differential line receiver as LDVS interface. The Si570 exists in many different versions. This project deals with the 10 - 215 MHz LDVS version.

As the controler I used an AVR AT90S2313 for the first tests (March 2008) and later (April) I changed the uC to the ATmega8515. Both are programmed by the language BASCOM-AVR.

I think my DDS (AD9951/54) software is more simply as the Si570 firmware. Anyone who intends to use the Si570 MUST struggle with the data sheet. The firmware is the result of much blood, sweat and beers but now it works with an rotary encoder and a LCD.