В примерах HAL смотрели? Там ......\Projects\STM32F429I-Discovery\Examples\FMC\FMC_SDRAM\Src\ http://www.st.com/web/en/catalog/tools/PF259243 /* Read back data from the SDRAM memory */
for (uwIndex = 0; uwIndex < BUFFER_SIZE; uwIndex++)
{
aRxBuffer[uwIndex] = *(__IO uint32_t*) (SDRAM_BANK_ADDR + WRITE_READ_ADDR + 4*uwIndex);
}