Q:

Do we have any document describing migration from the C24x CPU to the C28x?

A:

We have information on migrating code from a 24x core to the 28x core.  It is in appendix B and C of the TMS320C28x CPU and Instruction Set Reference Guide www.ti.com/lit/SPRU430

One thing to note is the 28x is a much better C engine then the 24x was.  I think many customers that have gone down this route in the end just rewrote things in C.

Apart from the core change, there are many differences between the 240x & Piccolo (Operating frequency, package, Supply rails required, Presence of onchip POR/BOR/VREG/internal-oscillators etc etc). Even on peripherals that exist on both devices (SCI/SPI) , there are differences like presence of a FIFO.