Direct access to Bitmap

Question

Hi,

In Embedded Wizard 8 there is a new feature useful to add put in ROM the Bitmap and/or Strings.

when i set Direct Access instead of Compressed I enable this feature. My question now is if it's possible to put the ROM in a external memory not directly accessed my MCU. (I need to use FlashRead(address) to access the memory).Is this available with DirectAccess function?

Thank you and best regards

Michele

Answer 1

Hi Michele,

if you are using the attribute 'DirectAccess' for the FormatOfBitmapResources and/or FormatOfStringConstants, then these resources are accessed directly from ROM, instead of decompressing and loading them into the RAM.

This direct access means, that strings are used directly by CPU or that bitmaps are accessed directly by the DMA2D graphics accelerator. Therefore, these resources have to available in the memory range of the microcontroller. Especially during animation sequences the bitmap resources are drawn many times directly from ROM into the framebuffer.

For 'DirectAccess' it is necessary that the linker/locater defines the addresses of all resources. If you want to load your own images via some FlashRead() function, then the ExternBitmap infrastucture might be a solution for you. But in this case, the bitmaps have to be loaded into RAM to be used by DMA2D.

Best regards,

Manfred.