Using resources directly from flash without decompression

Question

In some hardware environments the available RAM is very limited, especially if there is only on chip memory (SRAM) available. In case there is enough external flash memory available, the following questions arise:

Is it possible to use resources directly from flash without decompressing?

How to save RAM?

Answer 1

String constants and bitmap resources can be stored uncompressed within the flash memory and used directly from the flash memory without the need to decompress and load them into the data memory (RAM):

Setting the attribute ModeOfStringConstants to DirectAccess ensures that all string constants are stored uncompressed within the flash memory so that there is no need to load them into RAM during runtime. Please consider that uncompressed string constants require more flash memory than compressed string constants.

Setting the attribute ModeOfBitmapResources to DirectAccess ensures that the bitmap pixel information of the bitmap resources are stored uncompressed within the flash memory. These type of bitmaps are drawn directly from the flash memory without the need to load them into the RAM during runtime. Please consider that uncompressed bitmap resources require more flash memory than compressed bitmap resources.

Font resources are always stored compressed in the flash memory, but only the required glyphs of a font resource are loaded into a small glyph cache during runtime.

Further hints to save RAM can be found in the chapter Optimizing the Data Memory (RAM) usage.