The basic premise of the project is as follows;

1. The oscillator is to be controlled through the Flex Kenwood CAT command set through a serial port or a USB port with the appropiate hardware. ASCII commands would be sent to the controller asking for status or asking that a new frequency be set.
2. Be able to use pushbuttons, joystics, encoders and similar means to manually control the oscillator.
3. Be able to permanently contain settings for band limits and have control of relays to activate and select front end filters.
4. When project is finalized, create PCB using SMT components to contain entire system, OSC+Band Filters in a small "black box" componet to be used in multiple projects.

Since this would be a not too tiny yet not too massive project that can be done in stages I will be using it as a test vehicle to play with different CPU chips that I'm not too familiar with. So what are the CPU choices their advantages and disadvantages?

PicAxe specifiucally the 28X1 chip

1. + Inexpensive and easy to work with, available in different sizes to meet project requirements. can be programmed 100K times, has I2C for the 18X and higher chips.
2. + Easy to program, free programming tools available, it uses a built in Basic interpreter, lots of user groups with code and assistance.
3. - Lacks the built in data types to make the large number calculations required to program the SI570. This in itself is a major minus since I'm determined that the PC will not know anything about the device it's controlling, it just sends a frequency command and the controller's job is to figure out how to comply.

PIC controller in the 18F  family, specifically the 18F2550

1. + Low cost ($5), yet very capable 32KB Flash, built in USB port a big plus, 48MHz, EEPROM, I2C, SPI, Serial
2. + Free development software (C and Assembler), inexpensive debug hardware.
3. + Free resident FORTH Compiler/Interpreter available, a big plus since FORTH is ideal for hardware development.
4. + Inexpensive prototype boards available from SparkFun
5. + Chip is available in DIP and QFP versions to make development easier.

AVR ATMEGA series, specifically the ATMEGA168 CPU

1. + Low cost ($3.5) very capable, 16KB Flash, EEProm, I2C, SPI, 20MHz, Serial
2. + Free development software (C and Assembler) plus Pascal, and Basic, inexpensive debugging tools.
3. + Possible free FORTH resident Compiler/Interpreter (I have seen it but I don't remember where)
4. + Inexpensive very capable Basic compilers are available for less than $100
5. + Inexpensive development boards from SparkFun
6. + Chips available in DIP and QFP for easier development.

AVR Butterfly

1. + Same advantages as the AVR ATMEGA chips mentioned above
2. + Built in display and input buttons including a joystick and serial port to program and use in controlling the device.
3. + Inexpensive prototype board available from Smiley's to hold the Butterfly, add voltage regulation, and have a decent breadboard area.

MSP430 family specifically the 430F1213 and the 430F1611 which is way overkill but I have other interest in using this chip.

1. + Parts are inexpensive, more powerful it's 16 bits instead of previous 8 bit CPUs, 48KB Flash, EEProm, 10K RAM, I2C, SPI, Serial
2. + Free development software (C Assembler), inexpensive debugging tools.
3. + Free Forth compilers available, runs Forth very efficiently due to it's 16 nature and it CPU architecture.
4. + I own a copy of the ImageCraft Professional C compiler for the MSP430 family.
5. + Even though DIP packaging is not available SparkFun has inexpensive header boards.
6. + Inexpensive development boards available from SparkFun
7. + I'm more familiarwith it than any other choice, this CPU has the most easy to work with instruction set, I love it.
8. + I need to finish my optimizing Forth compiler for this CPU. (Fun Factor)

Which one I will use first? I'm not sure but I lean towards the Butterfly, since it will benefit a lot more people, but then there are probably a lot of people working on similar projects with the Butterfly already. The one I find more interesting is the PIC 18F2550, I have never worked with a PIC before and I'm wondering how easy it is to work with.

During the Holiday time off I'm trying to decide so I have been installing the different development systems, and I will be connecting my CPU prototypes to the PC and see which one is interesting and fun.