I figured out why I can’t properly save a bitmap after reading the source code at github.com/Seeed-Studio/DSOQuad … ce/Files.c
Why are you using such a primitive implementation of the FAT file system that doesn’t even support file creation? Is the flash memory space of the STM32 a limitation? It shouldn’t be… I usually use Elm Chan’s FatFs when I need a FAT file system on a microcontroller. It would be super easy for it work with the DSO Quad’s BIOS functions.
Also why not carry a template copy of the bitmap file instead of forcing the user to pre-create it? It’s only a couple of bytes worth of header data.
I don’t even see the document creation process in detail anywhere, but the fact is that the user must create the file in a very exact format first, so I expect this to either be documented very well, or for the code to create the file for you