Hi Alex_CF
I haven't used the MCF5485 so will not try to analyse the code.
However a bus error will probably occur if the DMA controller doesn't have the privilege to access the resources it is trying to access.
If it is from RAM, look at the RAMBAR settings (or other related ones) to see whether the DMA controller has been allowed to access RAM.
If it is from FLASH, check FLASHBAR (if there is one in the device) and other similar controller settings. If the DMA controller is accessing FLASH it may be necessary to use its backdoor address rather that its direct address (this is the case for the Coldfire devices that I work with - M5223X and M5213).
Maybe you will find something there. It can be quite tricky to work out what is blocking so be prepare to experiment with the debugger or search for reference initialisation code for your device.
Regards
Mark Butcher
www.mjbc.ch / www.uTasker.com