The issue may be that I have declared the read buffer in D2 SRAM.
I am not using this buffer yet, just the fact to declare it gets f_open to fail.
Also, if I declare another 32-bit aligned variable right before or right after the read buffer declaration, f_open works.
I must be doing something fundamentally wrong with the read buffer declaration!
Read buffer declaration (global variable):
// uint8_t Test __attribute__ ((aligned (32))); // f_open works when this line is active
uint8_t __attribute__((section(".dma_buffer"))) rtext[64] __attribute__ ((aligned (32)));
// uint8_t Test __attribute__ ((aligned (32))); // f_open works when this line is active
Linker file:
SECTIONS
{
/* DMA buffers in RAM_D2. RAM_D2 D-Cache is then disable via MPU */
.dma_buffer 0x30000000 :
{
KEEP(*(.dma_buffer)) /* keep variable even if not referenced */
} >RAM_D2
...
at the start of main() I enable D2 SRAM as follow:
__HAL_RCC_D2SRAM1_CLK_ENABLE();
__HAL_RCC_D2SRAM2_CLK_ENABLE();
__HAL_RCC_D2SRAM3_CLK_ENABLE();
