This is my final goal for this project series, consisting of a CPU controlling a SI570 and getting it's command from a PC via a USB port. This project is not just for a softrock, but will allow it to be used as a general purpose frequency generator from 10KHz to about 150 MHz

Project goals;

1. USB communitation to PC
2. Set and read frequencies from PC
3. Accurate crystal clock to allow frequency measurements.
4. Frequency counter mode.
5. General purpose frequency generator mode. 10KHz - 150MHz
6. Self calibration mode.
7. Optional frequency multiplier for use as a SoftRock clock(4X) of a generat purpose Frequency generator(1X).
8. Controlled  divide by circuits (/1000) to allow lower than 10MHz clocks.

Hardware required;

1. Higher capacity CPU, either a 18F2550 or a ATmega16 class CPU with USB capability.
2. Output divider chain and multiplexer to select clock source.
3. The use of high speed logic to handle 150Mhz
4. Ouput to control band-pass filter switching relays.

This project is a ways off.