OMAP-L138 External McBSP Frame-Sync

I like to periodically transmit 2048 Bits from an OMAP-L138 to an TMS320F28x3x. A McBSP seems to be a good idea. The idea is to transmit one big frame (single phase, 64 * 32 bits). With one Frame-Sync it is easily possible to detect the frame boundary without any additional work from the C2000 CPU.

I've one problem. The Frame-Sync must be generated externally (because this signal is precisely synchronized to another master). Unfortunately there is no external clock source available, which means that the clock should be generated with the McBSP clock generator. I see at least one problem: The external Frame-Sync must be synchronized to the internal Clock (e.g. with a D-Flip-Flop). Is there any potential other problem?