Does it run on machines without an MMU, like the Blackfin?
Not right now, and probably not in the future. Without an MMU it is not possible to run the popular servers OSes, like Linux. ucLinux is well supported on the Blackfin, but ucLinux is a cut down Linux, designed to live within the limitations a lack of an MMU imposes. Some other telephony software has been ported to Blackfin based boxes, like the IP04 at http://www.rowetel.com. If the application is clean and simple, the results can be very satisfactory. However, users must take care not to run tasks with can result in ever increasing memory fragmentation. If they don’t, frequent reboots may be required. So far a version of FreeSWITCH has not been defined which lives with such restrictions. Therefore, no port to a ucLinux platform has so far been undertaken.