Posted on February 18, 2016 at 23:14Hi,
if you are out of internal SRAM space - two options:
a) If your data, e.g. a background image for LCD, a huge look-up table ... has const data (just read, no need to modify) - you can put it into FLASH (ROM). This is done automatically by adding ''const'' to the C-code array definition.
b) You can also use external SDRAM. Just enable it via the SystemConfig function. BTW: if you use the LCD it should be already enabled, the frame buffer for LCD is on SDRAM.
So, you should have a huge amount of SDRAM.
Just: the linker does not know your SDRAM (sure, not available at boot time, no way to let load code via debugger there). You have to manage and organize the data and access to SDRAM yourself. Best is to use the macros which define base address and size of SDRAM and use a pointer to SDRAM.
BTW: if you have a data array in image (code) and you want to have it on SDRAM - you had to memcpy() during runtime to SDRAM: SDRAM is not loaded by debugger and only available after your system init was executed.
Other option is: QSPI (I use it already): you can enable QSPI flash device and map it (as NOR). It would become readable as any other memory, but not write-able: you had to flush the QSPI with your data (e.g. LCD images, pictures, audio files ...) using the ST-LINK utility. Works great for huge data (as RO, const), just a bit slow, but working transparent in C-code as any other RO memory.
