A tip for time-critical code

[w9ran]

For those like me who are new to multicore, it's easy to think that what happens on one core has no effect on the other, but it can happen. In my case, a waveform generator on core1 was being interfered with by a user interface on core0, causing random interruptions in the output from the PIO. The solution was to apply the __not_in_flash_func macro to run the time-critical code from RAM, preventing flash contention problems. Just thought I'd note this for others who might run into a similar issue in the future.