Posted on October 06, 2015 at 16:33Porting a reasonably sized app from an F1 to F2 under the SPL took under a day for the core functionality, most of the effort was dealing with the different pin configuration methods. The L1 should be more similar to the F2/F4 than the F1 was.
If you're doing stuff at the register level, expect to take a lot longer dealing the bits and registers. The compiler might catch a lot of this, but you'll have to battle through the errors and warnings, and double check the manuals.
It's going to depend a lot on how well partitioned/abstracted your code is, and if you put in any thought to portability from the outset.
Sit down with the manuals, and compare-n-contrast the peripheral that are most critical to your design, and gauge how different they are.
