I use the 390 with FLASH (29F002). Some advantages of the 390 over the Cygnal type:
-2 CAN ports
-2 serial ports
-large adress range
I have a bootloader which can reprogram the application. Everything works fine so far but I use only 64k for Code, so it is a standard 8051 memory model. I use only 22MHz but could go up to 33MHz with the same chips. 74ACxx types are required for adress decoding.

Werner