Hi SteveT
One can write great lengths about the pros and cons of individual chips and development environments so I will restrict this to a few initial comments on the Coldfires and the Luminary Micro with internal PHY.
1) The Coldfire development package is a strong incentive to use these parts. If one orders a demo board one has more or less everything to complete a project - the special compiler edition is often adequate (128k code size limit) and in the worst case an additional debugger needs to be purchased. Most people stick with CodeWarrior so all is very standardised.
2) Luminary boards also contain debuggers and can be used as debuggers to other boards too. They are a bit slow (as debuggers) but usable. There is generally a greater choice for development environment and so ARM projects tend to be less standardlised in this respect. It can be a bit overwhelming as a new user of these chips to decide on the development environment and debugger to choose for first project work.
3) The M5223X and M5225X allow a good choice between an integrated PHY solution or an external one (with additional benefits of more memory, a memory interface and USB). The external PHY will generally be more flexible (auto-crossover etc.) and lower power, but requires more space.
4) Some Luminary parts have integrated PHY with auto crossover and have a surprisingly good power consumption (the chips get less hot) -
http://www.utasker.com/forum/index.php?topic=126.0. The newer parts have large memory and also USB and so are very impressive.
5) The Coldfire parts are very mature and also very popular for uTasker based projects. At the moment I would be more nervous with a Luminary part due to the fact that they have recently been taken over by Texas Instruments and are still in a phase of being fully integrated. This means that supply of parts may be a concern until the production has been fully integrated (see the Luminary Forum, check stocks and delivery times). There have also been a number of errata being solved in newer silicon versions, so it may pay to observe the progress until the time is right to make the most of what they have to offer. (
Note that this is a personal opinion and progress changes with time so contact the company directly for up to date news).
6) One of the main goals for the uTasker project was to make development flexible concerning the part finally used. For this reason learning curves between changing parts (even mid-stream) should be minimum - this means that reacting to changes (newer parts, better features, better performance, better availability, etc.) becomes easier. Although of course at some point a commitment does have to be made;-)
Regards
Mark
