Extern Bitmap usage and performace from external sd/emmc flash memory

Question

Dear,

I would like to make use of extern bitmaps for our project that can be loaded for a non addressable flash memory. 

1) I found this tutorial https://doc.embedded-wizard.de/extern-bitmap-loader for that, but I wonder if you have any optimized library to convert stored bitmaps on a mounted sd into embedded wizard bitmaps. I have stored a .bmp file on a FAT mounted sd and read it using file system functions provided by the freertos.

2) During my analysis I also found this topic on your community: https://ask.embedded-wizard.de/5429/loading-resources-from-nand-flash?show=5429#q5429  , that shows an example of how to access a NAND flash using EwRegisterFlashAreaReader() function. 

Can you provide any example for the EK-RA8D1 demo board using the SDRAM to handle images stored on sd? 

Moreover, which is the better option from a performance point of view to access data from sd? using a mounted system (1) or direct access (2)? 

Thank you

Answer 1

Hello,

as you already mentioned, there are two different options: using Extern Bitmap (1) or using an external flash reader (2). These two approaches are not really comparable and the selection for one of these depends on the use case.

In case you want to load images dynamically during runtime (e.g. from a SD card via a file system), Extern Bitmap provides the suitable interface for that.

In case you want to store bitmaps, fonts or strings of your GUI application within a non addressable flash device (NAND flash), then you can separate these constant data from your binary and store them within your NAND flash. The flash reader is then accessing the resources during runtime on request and reading the necessary blocks from Flash to RAM.

Please let us know more details about your dedicated use-case, then we can find a good solution. As a customer, we can help you with further details about the flash reader. In this case, please contact us via support@embedded-wizard.de .

Best regards,

Manfred.