Safe implementation of framebuffer in external RAM #3
Description
Maybe we can use something like grounded for this: https://docs.rs/grounded/0.2.0/grounded/uninit/struct.GroundedArrayCell.html
Currently we just call the unsafe part once and rely on that being called only exactly once. Would be good to have that more properly done in the future. GroundedArrayCell seems like it is intended for something like these linker-section-bound framebuffer array.