Nios® V Embedded Processor Design Handbook

ID 726952
Date 5/13/2024
Document Table of Contents SDM Bootloader

The SDM bootloader is a HAL application code utilizing the Mailbox Client Intel FPGA IP HAL driver for processor booting. Altera recommends this bootloader application when using the configuration QSPI flash in SDM-based devices to boot the Nios® V processor.

Upon system reset, the Nios® V processor first boots the SDM bootloader from a tiny on-chip memory and executes the SDM bootloader to communicate with the configuration QSPI flash using the Mailbox Client IP.

The SDM bootloader performs the following tasks:

  • Locates the Nios® V software in the configuration QSPI flash.
  • Copies the Nios® V software into the on-chip RAM or external RAM.
  • Switches the processor execution to the Nios® V software within the on-chip RAM or external RAM.

Once the process is complete, the SDM bootloader transfers program control over to the user application. Altera recommends the memory organization as outlined in Memory Organization for SDM Bootloader.

Figure 15. SDM Bootloader Process Flow
  1. Nios® V processor runs the SDM bootloader from the on-chip memory.
  2. SDM bootloader communicates with the configuration flash and locate the Nios® V software.
  3. SDM bootloader copies the Nios® V software from the Configuration Flash into on-chip RAM / external RAM.
  4. SDM bootloader switches the Nios® V processor execution to the Nios® V software in the on-chip RAM / external RAM.