STM32H743 & ISSI IS42S32800G Self-Refresh Mode Problem

[BGeor.1]

After the firmware is up and running, I am trying to put the SDRAM in self-refresh mode. We are using FreeRTOS. In order to put SDRAM into self-refresh mode, I write 0x4480D to FMC_SDCMR register. I am using IAR debugger, and I execute the statement HAL_SDRAM_SendCommand(&hsdram1, &command, SDRAM_TIMEOUT); manually from the debugger. This way, I assume SDRAM should be in idle state when I am issuing the self-refresh command. I am only issuing the command to bank 2 since we use only bank 2 in our design. After I write the value to FMC_SDCMR, FMC_SDSR still says it is in normal mode instead of self-refresh mode. Below is the snippet of code that I am using.

  if(sleepEnabled)

   {

       /* Step 5: Program the external memory mode register */

       tmpmrd = (uint32_t)SDRAM_MODEREG_BURST_LENGTH_8         |

           SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL  |

           SDRAM_MODEREG_CAS_LATENCY_2          |

           SDRAM_MODEREG_OPERATING_MODE_STANDARD |

           SDRAM_MODEREG_WRITEBURST_MODE_SINGLE;

        command.CommandMode = FMC_SDRAM_CMD_SELFREFRESH_MODE;

       command.CommandTarget = FMC_SDRAM_CMD_TARGET_BANK2;

       command.AutoRefreshNumber = 1;

       command.ModeRegisterDefinition = tmpmrd;

        taskENTER_CRITICAL();

        /* Send the self refresh command */

       sdramStatus = HAL_SDRAM_SendCommand(&hsdram1, &command, SDRAM_TIMEOUT);

       // *(uint32_t *)SDCMR = data;

        while(1);

        taskEXIT_CRITICAL();

   }

Anyone has ran into this problem? Any suggestions?